The coexistence of humans and rodents lasts from the beginnings of the history of agriculture. Many rodent populations accepted to synanthropic way of life and as commensals accompany human societies until today. In the first study we wanted to find out, how the evolution of non-commensal rodent species, a Cypriot mouse (Mus cypriacus), was influenced by people. This endemic island species evolved on the Cyprus Island without presence of any mammalian competitors or predators. In last 10.000 years humans arrived on the island, bringing several mammalian species, which affected the environment markedly. A black rat (Rattus rattus) is now dominant species there and presumably it is an important competitor for the Cypriot mouse. We supposed that the mice should avoid its odour. Nevertheless the rats odour was preferred by the mouse, probably as an odour of phylogenetically related species. On the contraty, the odour of domestic cat (species, which is also widespread on the island), was avoided. In conclusion, the long-term isolation from mammalian predators did not affect the antipredatory reactions of the Cypriot mouse. Our next study was focuse on changes in behavioural strategies of different populations of mice: the main question was how the commensal way of life affects their exploratory...

Rodents often colonise agricultural lands and become pests that cause economic loss and crop damage. Eradicating or regulating pest numbers has economic and environmental costs and has always been of great interest to farmers and nature conservationists. To reduce rodent numbers poison baits are used more often than biological control. However, poisoning has adverse environmental impacts and ignores the underlying biological factors that influence pest abundance. This study examined the interactions of the common rat species of oil palm plantations, namely Rattus rattus diardii, R. argentiventer and R. tiomanicus, with their food resource, habitat structure and introduced predators in an attempt to provide a better understanding and approach for their control. To investigate the interrelationships among rodents, owls and oil palms, rodent trapping was conducted simultaneously with pellet collection and assessment of the breeding of owls over six study plots and seven trapping intervals in one oil palm plantation. Trapping records suggested that relative abundances of rodent species differed in plots with palms of differing ages. There were more R. r. diardii as a proportion of the total captures in older palms (seven years old) while R. argentiventer was the most common rat captured in younger palms (three years old). The abundance of R. tiomanicus remained low throughout trapping sessions for palms of all ages. A numerical response of rats to fruit availability in older palms was demonstrated by a positive and significant correlation between the numbers of fruit bunches present and the total number of rats captured. This relationship was observed in both older and younger palms only for R. argentiventer but not R. r. diardii or R. tiomanicus in either age of palms. This suggests that the competitiveness of R. argentiventer may be higher than that of the other two species providing that there were no factors other than food availability that limit the numbers of other two species. However, the levels of damage to palm fruit were significantly correlated with the relative abundance of R. argentiventer only in younger palms, not in older ones where R. r. diardii were more abundant. The more terrestrial nature of R. argentiventer may have restricted their acquisition of food when the palms became taller. In addition to differences in feeding niche, habitat heterogeneity may also be important in determining the rat species compositions at different ages of palms. Vegetation cover may act as a refuge for rats; the overall occurrence of rats, and especially R. argentiventer, was positively correlated with vegetation cover and height, and even certain vegetation associations. This study supported the continued use of the barn owl Tyto alba javanica for biological control of rodent pests in the palm oil plantations. The numbers of different rat species consumed by owls, as measured by pellet numbers, were proportional to prey captures with R. r. diardii dominating the prey items. Weights and sexes of rats, based upon sizes of bones recovered from owl pellets, indicated that the birds did not preferentially prey on any size or sex classes of rats. Although there was no differential predation by the owls, a functional, and possibly a numerical, response of the birds to changes in rat numbers was demonstrated. A functional response of barn owls to prey abundance was evidenced by a significant positive relationship between the relative abundance of rats captured and numbers of pellets collected. Some form of numerical response of barn owls was suggested by higher breeding records when rat abundances were significantly higher. Since both functional and numerical responses are important determinants of whether predators are likely to be able to regulate prey numbers, the role of barn owls as a practical biological control agent in oil palm plantations was supported. This study suggested that the regulation of rodent pests in oil palm plantations should not be limited to chemical measures but can be complemented by other biological factors including interspecific interactions, manipulation of the availability and density of food and habitat structure, in addition to predation by barn owls. The findings suggested that an integrated approach to rodent control, considering all biological factors that influence rat numbers, should be properly applied if an environmentally friendly and possibly cost effective approach is to be applied for the palm oil industry.

This study examined the effect of prolonged differential housing and/or diet following exposure to chronic restraint stress on body weight, body fat weight, body fat composition and corticosterone, glucose, insulin and leptin levels. To this end, male Wistar rats were individually-housed (IH) or pair-housed (PH) and fed a condensed milk diet (CD) or a mushy rat chow diet (MD) for twelve weeks. Subsequently, all rats underwent chronic restraint stress (CRS) for seven hours/day for four weeks. During CRS, only PH rats fed MD continued to gain weight, while growth of the other groups was stunted. Housing and diet impacted on body fat weights, where PH caused increased retrorenal fat (P<0.001) in rats fed MD, while in rats fed CD, PH gave rise to less visceral (P<0.01) and more interscapular (P<0.05) and retrorenal fat (P<0.001). The CD resulted in more retrorenal (P<0.001) and interscapular fat (P<0.05) in PH rats, with more visceral (P<0.001) and retrorenal fat (P<0.01) in IH rats. Housing influenced only the fatty acid profiles of the liver and subcutaneous fat in rats fed CD. The CD caused differing fatty acid profiles of the liver, subcutaneous fat, visceral fat, interscapular fat and muscle in PH rats, while altering the fatty acid profiles of the liver, subcutaneous fat, interscapular fat and muscle in IH rats. Housing and diet did not result in differences in corticosterone, insulin and glucose concentrations, while both resulted in significantly elevated leptin levels in PH rats fed CD. Therefore the types of housing and diet have various effects on body weight and glucose and fat metabolism following chronic stress. This dissertation is dedicated to My dear parents, Jeff and Avril Ackerman, for their on-going support My loving husband, Brandon, for his encouragement, assistance and patience My children, Elazar Tzvi, Sara Esther, Yaakov Yehuda and Rossi Bear who have been my stress alleviators and Idah Rangwato and Annah Sibanda who are my right-hand ladies and have made it possible to complete this dissertation- Thank you!

Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 147-160). / Microfiche. / xvii, 160 leaves, bound ill. 29 cm

Rodents cause significant damage to lowland rice crops across Cambodia and farmers are increasingly turning to chemical rodenticides for pest rodent management. Concern about the potential damage of these chemicals to human and environmental health provides the impetus for a search for alternative rodent management strategies, with particular interest in ecologically-based rodent management (EBRM). EBRM has a strong emphasis on non-chemical methods including the Trap Barrier System (TBS) and uses knowledge of pest rodent ecology to design effective interventions that limit population growth. For Cambodia, almost nothing was known at the start of this study regarding the identity, distribution and ecology of the country’s rodent pests. This research was designed to document this knowledge in parallel with a rodent management trial carried out at Somrong Commune in Kampong Cham Province of Cambodia, with the practical aim of informing on the outcomes of the trial and assisting with future development of EBRM in Cambodia. The large physical scale of the study and the relatively short time frame available for research led me to develop an action research approach that combined traditional positivist biological research with a more constructivist approach and participatory methods to gain access to and utilize local knowledge about rats. This research documents Cambodian pest rodents in lowland rice field cropping systems, through a combination of nation-wide collecting followed by detailed taxonomic assessments, and the use of farmer meetings and interviews to estimate the history and severity of the problem in each area. A total of nine rodent pest species were identified but both the pest rodent community and the severity of the associated problems vary from province to province. One species, the rice field rat (Rattus argentiventer), appears to be actively spreading and is not yet found in the northwestern provinces. A more detailed study in Somrong Commune found seven species and documented aspects of habitat use, breeding biology and movement. The inclusion of local knowledge in the study added a spatial and temporal scale to the study that could not have been obtained through conventional means, and which led to novel hypotheses about pest rodent ecology in the Somrong landscape, presented in the form of a heuristic landscape model. Criteria are developed for assessing the rigour and reliability or trustworthiness of the results. Particular attention is paid to the potential value of ‘expert’ knowledge which is rarely used in participatory research but which holds enormous potential for research into technical issues. The results of the TBS trial carried out in Somrong Commune were analysed to assess whether implementation of this method resulted in lower levels of rodent damage and higher rice yields relative to a single control commune, Lvea, and whether the farming community in Somrong is likely to adopt the method in the future. Although some farmer survey data suggest that yields improved in Somrong during the TBS trial, statistical analysis of the quantitative data set fails to yield compelling evidence of any benefit from use of TBS. The results emphasize the important role of landscape factors, especially the annual flooding cycle of the Mekong River, in determining the spatial and temporal distribution of rodent damage. Analysis of the relationship between rat captures and claimed yield increases also suggests that the TBS was not primarily responsible for the yield increase—too few rats were captured to account for the additional yield, even under extreme scenarios for how individual rodents cause damage to rice crops. Somrong farmers are unlikely to continue with the TBS method after completion of the project due to many perceived technical problems with implementing the method, and other concerns over its high labour and monetary costs. The ecological results of this study are used to suggest various alternative means by which Somrong farmers might combat the problem of rodent pests. Finally, a new approach is recommended for gaining an appreciation of rodent ecology on a landscape scale. This approach uses a combination of generalities about rodent biology and ecology, field observations, and incorporates local knowledge from local ‘experts’. This approach is likely to yield a faster and more complete understanding of the spatial and temporal dimensions of a local rodent community than more conventional approaches and will hopefully lead to more effective and relevant rodent management recommendations.

Thesis (M.Sc.)--York University, 2008. Graduate Programme in Higher Education. / Typescript. Includes bibliographical references (leaves 91-96). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38784

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Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2018-01-26T12:38:56Z No. of bitstreams: 1 2010 - Juberlan Silva Garcia.pdf: 6866273 bytes, checksum: 77b115c7b87deb998b7440f5ecb87940 (MD5) / Made available in DSpace on 2018-01-26T12:38:56Z (GMT). No. of bitstreams: 1 2010 - Juberlan Silva Garcia.pdf: 6866273 bytes, checksum: 77b115c7b87deb998b7440f5ecb87940 (MD5) Previous issue date: 2010-12-03 / The trematode Echinostoma paraensei parasitizes the small intestine of rodents, being its natural definitive host Nectomys squamipes. In spite of the great importance of echinostomatides, there are few studies on morphology, biology and physiology of E. paraensei and its interaction with their intermediate and definitive hosts. In the present study 50 Rattus norvegicus (Wistar),adult females were used, 35 were individually infected with 150 E. paraensei metacercariae (Sumidouro strain) and 15 were maintained uninfected, as control group. Weekly, seven infected and three uninfected rodents were euthanized using CO2.The blood was collected to hematological analysis, and serum obtained by centrifugation and used to aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALKP), gamma-glutamyl transferase (GGT), bilirubin, glucose, total proteins and fractions determinations. Fragments of liver were collected to glycogen determination and histophatological analysis. Adult worms were loaded until third week of infection, being the higher number of worms loaded at first week of inection. The hepatocytes had rounded edges, with signs of impaired nuclear, mild infiltration of polymorphonuclear and sinusoids slightly expanded. The hepatocytes were vacuolated with discrete perivascular and periportal lymphocytic infiltration. The serum biochemical parameters analyzed were increased at the first week of infection, varying onward. Hematological analysis revealed the development of normocytic and normocromic anaemia with anisocytic alteration. In the white blood cells, only a leukopenia was observed at the third week of infection. The present results are discussed. / O tremat?deo Echinostoma paraensei ? um parasito de intestino delgado de roedores, sendo seu hospedeiro definitivo natural Nectomys squamipes. No presente estudo, foram utilizadas 50 f?meas adultas de Rattus norvegicus (Wistar), 35 animais infectados individualmente com 150 metacerc?rias de E. paraensei (linhagem Sumidouro) e 15 animais n?o infectados (controle). Semanalmente, sete animais infectados e tr?s animais controle foram submetidos ? eutan?sia com CO2. O sangue foi coletado para an?lise hematol?gica, e o soro obtido por centrifuga??o, para as determina??es de aspartato aminotransferase (AST), alanina aminotransferase (ALT), gamaglutamiltransferase (GGT), fosfatase alcalina (ALKP), bilirrubina, glicose, prote?nas totais e fra??es. Fragmentos de f?gado foram coletados para a determina??o de glicog?nio e para a an?lise histopatol?gica. Vermes adultos foram recuperados at? a terceira semana de infec??o, sendo o maior n?mro de vermes recuperados na primeira semana. Os hepat?citos apresentavam-se com bordos arredondados e alguns sinais de comprometimento nuclear, infiltra??o por polimorfonucleares nos sinus?ides, vacuoliza??o, discreta infiltra??o linfoplasmocit?ria perivascular e periportal com poucas c?lulas mononucleares presentes na luz do ducto biliar, alguns hepat?citos estavam hipotrofiados. As an?lises hematol?gicas revelaram o desenvolvimento de uma anemia normoc?tica normocr?mica, com anisocitose. N?o foram observadas altera??es significativas na s?rie branca, havendo apenas uma leucopenia na terceira semana de infec??o. Os resultados obtidos s?o discutidos.

Le rat (Rattus spp.) est une source de nombreux pathogènes zoonotiques responsables de morbidité et de mortalité dans le monde. Ces espèces sont particulièrement problématiques en santé publique car leur mode de vie synanthrope favorise la proximité rat-Homme et la transmission potentielle de pathogènes. Selon l'approche « une seule santé », la surveillance sanitaire des rats et d'autres espèces animales sensibles devrait contribuer à améliorer la santé de ces dernières et de l'Homme. Notre objectif était de développer la surveillance des zoonoses associées aux rats chez une espèce source (R. norvegicus) et chez des espèces cibles (bovins, chiens et porcs) en tant que sentinelles de l'exposition de l'Homme. L'intérêt de méthodes de détection dont la micro-puce à ADN développée dans le cadre du projet européen « WildTech » et l'investigation de la distribution du risque étaient les thèmes majeurs de ces travaux. Ils ont été documentés à partir de 181 rats capturés dans le Rhône entre 2010 et 2013 et, de données diagnostiques de leptospiroses animales enregistrées au Laboratoire des Leptospires – Lyon entre 2008 et 2012. Les méthodes de détection directes et indirectes utilisées à des fins de surveillance ont montré leur intérêt par la mise en évidence de quatre pathogènes potentiellement zoonotiques chez les rats (Hantavirus Séoul, virus de l'hépatite E, Leptospira spp. et Toxoplasma gondii). Malgré la spatialisation hétérogène des statuts infectieux, Leptospira spp. et l'hantavirus Séoul étaient les dangers prédominants avec respectivement, 26%, CI95%=20%-33% et 14%, CI95%=8%-20% de rats infectés par ces agents. Leur distribution spatiale a été caractérisée par des indices socio-économiques et, dans le cas des infections par les leptospires, une étude approfondie des souches circulantes a montré que leur persistance relevait de facteurs locaux, intrinsèques à la colonie. L'étude des leptospiroses animales (chiens et bovins) suggère leur exposition accrue au sérogroupe Australis, leur distribution spatiale hétérogène et une croissance significative de l'incidence annuelle canine. Ces trois observations également rapportées chez l'Homme soulignent l'intérêt de la surveillance de ces espèces en tant que sentinelles. Les informations obtenues par l'ensemble des méthodes appliquées contribuent à une meilleure compréhension de l'épidémiologie des zoonoses associées aux rats et de la leptospirose en particulier, afin d'orienter la mise en œuvre de leur surveillance et les décisions de santé publique à venir. / Rats (Rattus spp.) are a source of a number of zoonotic pathogens responsible for morbidity and mortality worldwide. These species are particularly problematic with regards to rat associated health risks because rats are living in close contact with people leading to potentially rat disease transmission. Based on the "One Health" approach, surveillance of zoonotic pathogens in rats and other susceptible hosts should help to improve animal and human health. Our aim was to develop the surveillance of rat-associated zoonoses in a source species (Rattus norvegicus) and, in some target populations (cattle, dogs and pigs) as sentinels of human exposure. The screening methods including DNA microarray developed for the purpose of the "WildTech" project and the spatial distribution of the risk were the major themes in this work. They have been documented based on 181 rats captured in the administrative unit “département du Rhône” between 2010 and 2013 and, diagnostic data of leptospirosis in cattle, dogs and pigs, recorded at "Laboratoire des Leptospires – Lyon" between 2008 and 2012. The application of various screening methods (direct and indirect) for the purpose of surveillance were relevant and detected four potentially zoonotic pathogens circulating in rats, (hantavirus Seoul, hepatitis E virus, Leptospira spp. and Toxoplasma gondii). Although the location of infected rats varied among a short geographic distance, Leptospira spp. and hantavirus Seoul were the predominant hazard with respectively 26%, IC95% = 20% -33% and 14%, IC95% = 8% -20% of infected rats. Their spatial distribution could be characterized with socio-economic indices and, regarding Leptospira-infected rats, a further study shown that the maintenance of strains was related to local and intrinsic factors. The study of leptospirosis in dogs and cattle revealed their increased exposure to the serogroup Australis, their heterogeneous spatial distribution and the significant increase of annual incidence in dogs. The same trends were observed in humans which underlines the relevance of surveillance of animal leptospirosis as sentinels of human exposure. All together, the information obtained contributes to a better understanding of the epidemiology of rat-associated zoonoses to support implementation of surveillance and public health decisions in the future.

Made available in DSpace on 2015-03-26T13:47:25Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1265748 bytes, checksum: 6ec2ab64f2ffff7c785ba2692dabdda0 (MD5) Previous issue date: 2013-11-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This dissertation was carried out in two subprojects, with the first being entitled Clinical and biomechanical analyzes of the common calcaneal tendon of Wistar rats underwent laser therapy associate or not to eccentric exercise , and the second Histomorphometric analysis of the common calcaneal tendon of Wistar rats treated with laser therapy and eccentric exercise . The first subproject aimed to evaluate the effect of low-level laser therapy associated to eccentric exercise (downhill walking) on tendinopathy of the common calcaneal tendon of Wistar rats, by clinical and biomechanical analyzes, while the second subproject, by means of histopathological and morphometrical analyzes. Sixty-three adult male rats were randomly distributed into the following groups: L (laser), E (eccentric exercise), LE (laser and eccentric exercise), R (rest), CT (contralateral tendon) and H (healthy tendon). The last two groups were present only in the first subproject. Unilateral tendinopathy with induced lesion was done by transversal compression followed by scarification of the tendon fibers, except in animals of group H. The treatments laser therapy (904 nm/3 J/cm2) and, or eccentric exercise (downhill walking; 12 m/min; 50 min/day; 15o inclination treadmill) began 24 h after surgery and remained for 20 days. The animals were submitted to physical evaluation (painful sensitivity and locomotion capacity examination) every three days, with euthanasia performed 3, 7, 14, and 21 days after lesion induction, except in the animals submitted to clinical and biomechanical analyzes, with this procedure being conducted only on day 21. During euthanasia, a macroscopic evaluation of the lesion site was carried out and the transversal diameter of the tendon was measured (analayzed only the first subproject). Sequentially, 18 tendons (from 15 rats) were collected and frozen at -20oC until biomechanical test, on which the characteristics maximum load (N), stress at ultimate tension (MPa) and maximum extension (mm) were analyzed. For the histomorphometric analysis, the following characteristics were studied: hemorrhage, fibrinous tissue adhesions, epitendon thickening, organization and amount of collagen fibers and blood vessels, inflammatory infiltrate and fibroblasts, as well as collagens (type I and III) and connective tissue organization. Local edema was observed on the xi first 72 h postoperative, but no pain was detected under physical examination. The macroscopic evaluation performed in the first subproject rats showed no increase in the transversal diameter of the tendons, and no presence of fibrous adhesions. However, this last characteristic was observed in an animal in the rest group, and in another in the laser therapy group, during the one week evaluation in the second subproject. In clinical and biomechanical analyzes, the group submitted to the eccentric exercise presented the lowest (p=0.0000) locomotion capacity among the injured animals (including those in the rest group), while in second subproject, such result was presented by the group underwent to rest (p=0.0008). No difference occured between groups, even when considering healthy and collateral tendons, in the evaluated biomechanical characteristics maximum load (p=0.4379), stress at ultimate tension (p=0.4605) and maximum extension (p=0.3820). However, it was observed among injured tendon, that the LE group required greater load and strain to rupture. No difference was found among groups, or between times in the characteristics hemorrhage, formation of fibrinous adhesion, organization of collagen fibers and connective tissue organization. Considering the groups, regardless of time, it was observed that eccentric exercise caused epitendon thickening (p=0.0204), which was lower in the group submitted to laser therapy. Histological analysis showed difference (p=0.0032) in the number of inflammatory cells along time, being observed in greater amount only in exercised group. This result was confirmed by morphometric analysis, which demonstrated that there was significant interaction (group x time) in this caracteristic, where the eccentric exercise increased (p=0.0014) the inflammatory infiltrate over time (3 and 21 days), however, when associate with laser teraphy, there was reduction the inflammatory reaction. On the other hand, the combination of the treatments led to a greater angiogenesis in morphometric (p=0.0000) and histological (p=0.0006) analyzes, compared to the other groups, while the application of low-level laser alone reduced this characteristic along time. Animals kept at rest presented the lowest (p=0.0000) amount of fibroblasts in morphometric analysis. However, in the histological evaluation significant interaction (group x time) (p=0.0024) was observed. Greater amount fibroblast was observed in groups E, L and LE, the 7 th , 14 th and 21 st days, respectively. The animals who received laser and were exercised showed higher (p=0.0000) amount of collagen fibers along time. The use of low-level laser at the dose of 3 J and wavelength of 904 nm, associated to walking treadmill eccentric exercise began 24 h after surgically-induced tendinopathy in Wistar rats does not result in biomechanically xii tendon as resistant or elastic as a healthy tendon. On the other hand, the combination of treatments shows the advantage of increasing the amount of collagen fibers, reduce fibrinous adhesion and inflammatory infiltrate. However, the application of laser therapy alone is adequate for angiogenesis and tendon thickening prevention. Keywords: Achilles tendon; histomorphometrical and biomechanical analyzes of tendon, physical activity, therapy with laser. / A dissertação foi desenvolvida em dois subprojetos, sendo o primeiro intitulado Análises clínica e biomecânica do tendão calcanear comuns de ratos Wistar submetido à laserterapia associada ou não a exercício excêntrico , e o segundo Análise histomorfometrica do tendão calcanear comum de ratos Wistar tratado com laserterapia e exercício excêntrico . O primeiro subprojeto teve como objetivo avaliar o efeito da terapia com laser de baixa potência associada a exercício excêntrico (caminhada em declive) na tendinopatia do tendão calcanear comum de ratos Wistar, mediante análises clínica e biomecânica, enquanto no segundo por meio de análises histopatológica e morfométrica. Foram utilizados 63 ratos machos, adultos, que foram distribuídos aleatoriamente nos grupos L (laser), E (exercício excêntrico), LE (laser e exercício excêntrico), R (repouso), CL (tendão contralateral) e S (tendão sadio). Os últimos dois grupos existiram apenas no primeiro subprojeto. Tendinopatia unilateral com lesão induzida foi realizada mediante compressão transversal seguida por escarificações das fibras dos tendões, exceto nos animais do grupo S. Os tratamentos laserterapia (904 nm/3 J/cm2) e/ou exercício excêntrico (caminhada em declive; 12 m/min; 50 min/dia; esteira com 15o de inclinação) iniciaram 24 h após cirurgia e permaneceram por 20 dias. Os animais foram submetidos à avaliação física (sensibilidade dolorosa e exame da capacidade motora) a cada três dias, com eutanásia sendo realizadas 3, 7, 14 e 21 dias após indução de tendinopatia, exceto nos animais submetidos às análises clínica e biomecânica, cujo procedimento foi realizado apenas aos 21 dias. Durante a eutanásia foi realizada avaliação macroscópica do local da lesão e o diâmetro transversal do tendão foi mensurado (analisado apenas no primeiro subprojeto). Na sequência, 18 tendões (provenientes de 15 ratos) foram obtidos e congelados a -20oC até o momento do teste biomecânico, onde foram analisadas as características carga máxima (N), tensão na carga (MPa) e extensão máxima (mm). Para a análise histomorfométrica as seguintes características foram estudadas: hemorragia, aderência tecidual fibrinosa, espessamento do epitendão, organização e quantidade das fibras colágenas e dos vasos sanguíneos, infiltrado inflamatório e fibroblastos, assim como colágenos (tipo I e III) e viii organização do tecido conjuntivo. Edema local foi observado nas primeiras 72 h do pós- operatório, mas não foi constatado dor durante exame físico. Não houve aumento no diâmetro transversal dos tendões nem presença de aderência fibrosa na avaliação macroscópica realizada nos ratos do primeiro subprojeto. Entretanto, essa última característica foi observada em um animal deixado em repouso e outro submetido à laserterapia na avaliação realizada com uma semana no segundo subprojeto. Nas análises clínica e biomecânica, o grupo submetido a exercício excêntrico apresentou menor (p=0,0000) capacidade de locomoção entre os animais lesionados (incluindo os do grupo em repouso), já no segundo subprojeto foram os ratos mantidos em repouso (p=0,0008). Não houve diferença entre grupos, inclusive considerando-se os tendões sadios e contralaterais, nas características biomecânicas carga máxima (p=0,4379), tensão na carga (p=0,4605) e extensão máxima (p=0,3820) avaliadas. Entretanto, foi observado entre os tendões lesionados, que os do grupo LE necessitaram maior carga e tensão para se romperem. Não houve diferença entre grupos nem entre tempos nas características hemorragia, formação de aderência fibrinosa, organização das fibras colágenas e organização do tecido conjuntivo. Considerando os grupos, independentemente do tempo, foi observado que o exercício excêntrico acarretou espessamento do epitendão (p=0,0204), que foi menor no grupo submetido à laserterapia. A análise histológica apresentou diferença (p=0,0032) na quantidade de células inflamatórias ao longo do tempo, sendo observado em maior quantidade no grupo apenas exercitado. Esse resultado foi confirmado pela análise morfométrica, que demonstrou haver interação significativa (grupos x tempo) nessa característica, onde o exercício excêntrico aumentou (p=0,0014) o infiltrado inflamatório ao longo do tempo (3 e 21 dias), porém, quando associado à laserterapia, ocorreu redução do reação inflamatória. Por outro lado, a associação dos tratamentos ocasionou maior angiogênese, nas análises morfométrica (p=0,0000) e histológica (p=0,0006), quando comparado com os demais grupos, enquanto a aplicação isolada do laser de baixa potência reduziu essa característica ao longo do tempo. Os animais mantidos em repouso foram os que apresentaram menor (p=0,0000) quantidade de fibroblastos na análise morfométrica. Já na avaliação histológica, houve interação significativa (grupo x tempo) (p=0,0024). Maior quantidade de fibroblastos foi observada nos grupos E, L e LE, nos 7 o , 14 o e 21 o dias, respectivamente. Os animais que receberam laser e foram exercitados apresentaram maior (p=0,0000) quantidade de fibras colágenas ao longo do tempo. A utilização do laser de baixa potência na dose de 3 J e comprimento de onda de ix 904 nm, associada ao exercício excêntrico caminhada em esteira, iniciados 24 h após tendinopatia induzida cirurgicamente em ratos Wistar não resulta em um tendão biomecanicamente tão resistente ou elástico quanto o tendão saudável. Por outro lado, a combinação dos tratamentos possui a vantagem de aumentar a quantidade de fibras colágenas, reduz a aderência fibrinosa e infiltrado inflamatório. Já a aplicação isolada da laserterapia é adequada para angiogênese e para evitar o espessamento do tendão. Palavras-chave: tendão de Aquiles; análise histomorfometria e biomecâmica do tendão, atividade física, terapia a laser.