Gelenkknorpel ist ein gefäßloses, hoch spezialisiertes Gewebe mit nur sehr begrenzter Regenerationsfähigkeit. Entstandene Läsionen werden bei natürlicher Heilung durch min-derwertigen Faserknorpel gefüllt. Ein vielversprechender Therapieansatz kommt aus dem Gebiet des Tissue Engineering. Dabei werden isolierte Chondrozyten in vitro vermehrt und anschließend in den Defekt eingebracht. In den letzten Jahren ist hier die 3 D-Kultivierung in patientenspezifischen Biomaterialien zunehmend in den Fokus der Forschung geraten. Ziel der hier vorgestellten Studie war es, die Tauglichkeit von Vollblut und Blutplasma als Aus-gangsmaterial für MACTs aufgrund makroskopischer Eigenschaften, Zellzahlentwicklung im Konstrukt, Zellvitalität und Syntheseleistung charakteristischer EZM-Marker zu untersuchen. Es wurde für diese Studie Knorpel aus den Fesselgelenken vier geschlachteter Pferde (2-16 Jahre) entnommen, mechanisch zerkleinert und anschließend mit Kollagenase A verdaut. Von einem 6 jährigen klinikeigenen Wallach wurde Vollblut in Citratröhrchen gewonnen, ein Teil zu Plasma weiterverarbeitet und beides bei -80 °C bis zur weiteren Verwendung Schock gefroren. Zur Herstellung der walzenförmigen Konstrukte mit den Maßen 9,6 cm2 x 4,7 mm, wurden 4,5 ml Vollblut bzw. Plasma mit je 3x106 Chondrozyten suspensiert und durch Zuga-be von CaCl2 zur Koagulation gebracht. Der Kultivierungszeitraum betrug 28 Tage in DMEM, angereichert mit 10% allogenem Serum und 1% Antibiotika. Die Konstrukte wurden an den Tagen 1, 14 und 28 auf Zellzahl, -vitalität und mithilfe qRT-PCR auf hyaline Knorpelmarker wie Kollagen Typ II und Aggrekan untersucht. Zudem wurden histologische und immunhisto-chemische Präparate der Konstrukte angefertigt. Die Zellvitalität betrug sowohl in den VB-, als auch in den BP-Konstrukten ≥95% bei steigen-der Zellzahl (bis zu 5x106 im Vollblutkonstrukt). Die MACTs beider Ausgangsmaterialien schrumpften auf eine Größe von 2 cm² x 2 mm. Histologisch konnten in beiden Konstruktar-ten mit der Alzianblaufärbung sGAG belegt werden. Darüber hinaus wurde der sGAG Gehalt mit dem DMMB Assay quantitativ ermittelt. Aggrekan, C-4-S, C-6-S und COMP wurden als wichtige Bestandteile der EZM immunhistochemisch angefärbt und waren ebenfalls in beiden Konstruktarten nachweisbar. Mit der qRT PCR konnte die Genexpression von Aggrekan, Kol II und Kol I über den zeitlichen Verlauf ermittelt werden. Es stellte sich heraus, dass sich sowohl die Genexpression von Aggrekan als auch die von Kol II, den beiden Indikatorprotei-nen EZMs des hyalinen Gelenkknorpels über den Kultivierungszeitraum absenkten. Dies deutet auf eine Dedifferenzierung der Chondrozyten hin. Die Expression von Kol I dagegen stieg um ein Vielfaches an. Auch das kennzeichnet eine Dedifferenzierung. Zieht man ande-re Studien heran, so ist die festgestellte Umstellung der Genexpression aber vergleichsweise niedrig, eine Dedifferenzierung weg vom chondrogenen Phänotyp in der hier vorliegenden Arbeit also weniger stark ausgebildet. Biokompatibilität mit und Abbaubarkeit im Empfängerorganismus konnten in dieser in vitro Untersuchung nicht evaluiert werden. Zusammenfassend kann man festhalten, dass VB und BP als Ausgangsbiomaterialien zur Herstellung von MACT geeignet sind. Inwieweit es gelingen wird, den chondrogenen Phäno-typ beispielweise durch mechanische Stimulation der eingesäten Zellen stärker zu erhalten, muss in folgenden Studien geklärt werden. Ebenfalls weiterer Forschungsbedarf ist bei den Eigenschaften Elastizität und Steifheit gegeben. Grundsätzlich gilt, dass MACTs auf VB- und BP-Basis einen einfachen, kostengünstigen und patientenspezifisch herstellbaren Therapie-ansatz für die Behandlung von Knorpeldefekten darstellen. / Articular cartilage is a vessel-free, highly specialized tissue with only very limited regenera-tive capacity. Resulting lesions are filled with inferior fibrocartilage by natural healing. A promising therapeutic approach comes from the field of tissue engineering. Therefore iso-lated chondrocytes are expanded in vitro and then placed into the defect. In the last few years the 3-D culturing in patient-specific biomaterials has come increasingly into the focus of research. Purpose of the present study was to evaluate the suitability of whole blood and blood plasma as a basic material for MACT based on macroscopic properties, development of cell number in the construct, cell viability and synthetic performance of characteristic markers. For this study cartilage from the four fetlock joints of slaughtered horses (2-16 years) were removed, crushed mechanically and then digested with Collagenase A. Whole blood was obtained in citrate tubes of a 6 year old gelding owned by the clinic, finished part to both plasma and shock frozen at -80°C until further use. To prepare the cylindrical constructs, measuring 9.6 cm2 x 4.7 mm, 4.5 ml of whole blood or plasma, each with 3x106 chondro-cytes were suspended and coagulated by the addition of CaCl2. The cultivation period was 28 days in DMEM supplemented with 10% allogenic serum and 1% antibiotics. The con-structs were evaluated on days 1, 14 and 28 on cell number, viability, and using qRT-PCR examination for hyaline cartilage markers such as collagen type II and aggrecan. In addition, histological and immunohistochemical preparations of the constructs were made. The cell vitality was in the WB, as well as in the BP constructs ≥ 95% with increasing cell number (up to 5x106 in whole blood construct). The MACTs of both basic materials shrink to a size of 2 cm x 2 mm². Histologically sGAG could be verified in both construct species by Alzianblau staining. In addition, the GAG content was determined with the DMMB assay quantitatively. Aggrecan, chondroitin-4-sulphate, chondroitin-6-sulphate and COMP as major components of the ECM were stained immunohistochemically and were also detectable in both types of constructs. Aggrecan, collagen II and collagen I were determined on the time course by qRT PCR gene expression. It turned out that the gene expressions of both, aggre-can and of collagen II, the two ECM protein indicators of hyaline cartilage lowered over the cultivation period. This indicates a dedifferentiation of chondrocytes. The expression of colla-gen I on the other hand increased to a multiple, also featuring a dedifferentiation. If one approached other studies, the observed change in gene expression is comparatively low. In the present work the dedifferentiation from the chondrogenic phenotype is less distinctive. Biocompatibility and biodegradability in the recipient organism could not be evaluated in this in vitro investigation. In summary, one should notice that VB and BP are suitable basic materials for the production of MACT. It has to be clarified by following studies, to what extent the chondrogenic pheno-type can be strengthened, for example by mechanical stimulation of cells sown. Also further research is needed on the given properties, e.g. elasticity and stiffness. Generally MACT based on WB and BP- is a simple, inexpensive and patient-specific produced therapeutic approach for the treatment of cartilage defects.

Bioanalytical chemistry is a challenging field, often involving complex samples, such as blood, plasma, serum or urine. In many applications, sample cleanup is the most demanding and time-consuming step. In the work underlying this thesis a novel dynamic miniature extractor, known as a hollow-fibre liquid-phase microextractor (HF-LPME), was designed, evaluated and studied closely when used to clean plasma samples. Aqueous-organic-aqueous liquid extraction, in which the organic liquid is immobilised in a porous polypropylene membrane, was the principle upon which the extractor was based, and this is discussed in all the papers associated with this thesis. This type of extraction is known as supported-liquid membrane extraction (SLM). The aim of this work was the development of a dynamic system for SLM. It was essential that the system could handle small sample volumes and had the potential for hyphenations and on-line connections to, for instance, LC/electrospray-MS. The design of a miniaturised HF-LPME device is presented in Paper I. The extraction method was developed for some weakly acidic pesticides and these were also used for evaluation. In the work described in Paper II, the method was optimised on the basis of an experimental design using spiked human plasma samples. Paper III presents a detailed study of the mass-transfer over the liquid membrane. The diffusion through the membrane pores was illustrated by a computer-simulation. Not surprisingly, the more lipophilic, the greater the retention of the compounds, as a result of dispersive forces. The main focus of the work described in Paper IV was to make the HF/LPME system more versatile and user-friendly; therefore, the extractor was automated by hyphenation to a SIA system. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: Manuscript.

Made available in DSpace on 2015-03-26T13:55:27Z (GMT). No. of bitstreams: 1 texto completo.pdf: 201389 bytes, checksum: b16c6cf09aae35c8ba2e6527547629ed (MD5) Previous issue date: 2007-03-14 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Aiming to evaluate spray-dried animal plasma (PSP) by piglets weaning at 28 days of age was made a experiment with 128 piglets of a 7.635 ± 0.103 kg initial body weight allocated in a experimental block design, composed by four treatments, eight replicates and four animals a replicate. The treatments used were: 1) Diets without spray-dried plasma (PSP) and with dried milk (LDP), from 29 to 42 days of age; 2) Diets with LDP and 2.8% of PSP from 29 to 35 days of age in the phase one and 2.0% of PSP from 36 to 42 days of age in the phase two; 3) Diets with LDP and 4.2% of PSP from 29 to 35 days of age in the phase one and 3.0% of SPP from 36 to 42 days of age and 4) Diets without LDP and 5.6% of PSP from 29 to 35 days of age and 4.0% of PSP from 36 to 42 days of age in the phase two. From 42 to 56 days of age (phase three) all treatments animals received initial diets without PSP. It was not verified effect (P≥0.10) of SPP inclusion on the average daily feed intake (ADFI), in the period one. On the period one it was verified linear effect (P≤0.10, IBN = 6.8371GPMD 3.5732CRMD) of the treatments over the bio-nutritional index and over the inclusion of PSP (P≤0.10; Ŷ = 0.1364 + 0.0100X) over the daily weight gain and that the feed conversion ratio got better as the level of PSP in the diets was raised. There was no effect of treatments over the diarrhea index. It concluded that the inclusion level of PSP in the first week post-weaning diets for 28 days of age weaning piglets is 5.6%. / Objetivando-se avaliar níveis de plasma sanguíneo em pó (PSP) em dietas para leitões desmamados aos 28 dias de idade foi realizado um experimento utilizando 128 leitões com peso inicial médio de 7,64 ± 0,103 kg, distribuídos em delineamento em blocos, composto por quatro tratamentos, oito blocos e quatro animais por unidade experimental. Os tratamentos usados foram: 1) Ração sem plasma sanguíneo em pó (PSP) e com leite desnatado em pó (LDP), dos 29 aos 42 dias; 2) ração com LDP mais 2,8% de PSP dos 29 aos 35 dias na fase um e 2,0% de PSP dos 36 aos 42 dias na fase dois; 3) ração com LDP mais 4,2% de PSP dos 29 aos 35 dias na fase um e 3,0% de PSP dos 36 aos 42 dias e 4) ração com 5,6% dObjetivando-se avaliar níveis de plasma sanguíneo em pó (PSP) em dietas para leitões desmamados aos 28 dias de idade foi realizado um experimento utilizando 128 leitões com peso inicial médio de 7,64 ± 0,103 kg, distribuídos em delineamento em blocos, composto por quatro tratamentos, oito blocos e quatro animais por unidade experimental. Os tratamentos usados foram: 1) Ração sem plasma sanguíneo em pó (PSP) e com leite desnatado em pó (LDP), dos 29 aos 42 dias; 2) ração com LDP mais 2,8% de PSP dos 29 aos 35 dias na fase um e 2,0% de PSP dos 36 aos 42 dias na fase dois; 3) ração com LDP mais 4,2% de PSP dos 29 aos 35 dias na fase um e 3,0% de PSP dos 36 aos 42 dias e 4) ração com 5,6% de PSP e sem LDP dos 29 aos 35 dias na fase um e 4,0% de PSP dos 36 aos 42 dias na fase dois. Dos 42 aos 56 dias, na fase três, ração de creche sem PSP foi fornecida para os animais de todos os tratamentos. Não se verificou efeito (P≥0,10) da inclusão de PSP nas dietas sobre o consumo de ração médio diário. No período um verificou-se efeito linear crescente (P≤0,10, IBN = 6,8371GPMD 3,5732CRMD) dos tratamentos sobre o índice bionutricional e crescente da adição de PSP (P≤0,10; Ŷ = 0,1364 + 0,0100X ) sobre o ganho de peso médio diário e a Conversão Alimentar melhorou à medida que se aumentou o nível de PSP na dieta. Não houve efeito dos tratamentos sobre o índice de diarréia. Concluiu-se que o nível de inclusão de PSP é de 5,6% no período um.e PSP e sem LDP dos 29 aos 35 dias na fase um e 4,0% de PSP dos 36 aos 42 dias na fase dois. Dos 42 aos 56 dias, na fase três, ração de creche sem PSP foi fornecida para os animais de todos os tratamentos. Não se verificou efeito (P≥0,10) da inclusão de PSP nas dietas sobre o consumo de ração médio diário . No período um verificou-se efeito linear crescente (P≤0,10, IBN = 6,8371GPMD 3,5732CRMD) dos tratamentos sobre o índice bionutricional e crescente da adição de PSP (P≤0,10; Ŷ = 0,1364 + 0,0100X ) sobre o ganho de peso médio diário e a Conversão Alimentar melhorou à medida que se aumentou o nível de PSP na dieta. Não houve efeito dos tratamentos sobre o índice de diarréia. Concluiu-se que o nível de inclusão de PSP é de 5,6% no período um.

(thesis): Basis: This diploma thesis follows the bachelor thesis that concentrates on the eating habits and water intake of blood plasma donors before plasmapheresis. Goals: The research had four goals: 1) explore to what extent does providing of the educational material influence the awareness of blood plasma donors. 2) To map subjective state of health and lifestyle of plasma donors regarding their physical activity, healthy, regular, varied diet, smoking and sleep schedule. 3) To explore the knowledge of regime measures and risk behaviour before donating blood plasma. To evaluate donors' eating habits and water intake before plasmapheresis and reveal potential deficiencies. 4) Evaluate the knowledge of a given problem with those respondents who were provided with educational material in comparison with those respondents who got no educational material. Methods: An educational material was created regarding regime measures of blood plasma donors. This educational material served as the basis for standardized anonymous questionnaire. Maintaining the ethical principles and with the ethical committee's approval, overall data of 40 respondents frequenting Haematology Department and blood transfusion of the Military University Hospital Prague. The sample consisted of two groups of randomly selected...

Orientadores: Marcio Zaffalon Casati, Antonio Wilson Sallum / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T19:00:36Z (GMT). No. of bitstreams: 1 Gurgel_BrunoCesardeVasconcelos_D.pdf: 2894613 bytes, checksum: b68eb32e96e2245f94ae9bfdc771987e (MD5) Previous issue date: 2005 / Resumo: O objetivo do presente estudo foi avaliar histometricamente o reparo ósseo obtido após a utilização do plasmarico em plaquetas (PRP) e/ou de membranas não reabsorvíveis no tratamentode defeitos ósseos peri-implantares, do tipo deiscência, criados cirurgicamente em cães. Foram utilizados 1O cães adultos, machos, sem raça definida, nos quais os pré-molares inferiores (P2,P3, P4)e o primeiro molar foram extraídos. Após 3 meses das extrações, os leitosparaos implantes foram criados e posteriormente 2 deiscências ósseas vestibulares bilaterais, sendo então inseridos 4 implantes dentais de titânio. As deiscências foram designadas aleatoriamente às seguintes modalidades terapêuticas: 1) controle; 2) ROG; 3)PRP;4) PRP + ROG. Após 3 meses do tratamento, os animais foram sacrificados e os blocos contendo os implantes e tecidos duros adjacentes processados para secções não descalcificadas. Na análise histométrica, os parâmetros avaliados foram o contato osso-implante, a área de preenchimento ósseo dentro das roscas, a área e a densidade de tecido ósseo formado na região fora das roscas. Análise deVariância foi utilizada para a análise estatística dos dados (p<O,O5). Os resultados demonstraram diferenças estatísticas significativas para todos os parâmetros analisados em favor dos grupos tratados commembrana (p<O,O5), no entanto, não foram observadas diferenças quando o PRP foi utilizado (p>O,O5). Dentro dos limites do presente estudo, pôde-se concluir ue o PRP não exerce efeitos adicionais no reparo ósseo e que a ROG promove uma maior formação óssea ao redor dos implantes dentais / Abstract: The aim of the present study was to evaluate, histometrically, the bone healing after utilizing the platelet-rich plasma (PRP) and/ornon-resorbable membranes on the treatment of peri-implant bone defects, deiscense type, surgically created in dogs. Ten mongrel male adult dogswere used; in which the threel ow premolars (P2,P3,P4) and the first molar were extracted. Three months after dental extraction, dental implants sites were created and lately two bilater albuccal bone dehiscence, in which four titanium dental implants were inserted. Dehiscences werer and omly assignedfor the following treatment: 1) contrai; 2) GBR;3) PRP; 4) PRP+ GBR. After 3 months, animais were sacrificed; dental implants and adjacent hard tissues were pracessed for undecalcified sections. At histometrical analysis,the parameter se valuated were bone-implant contact, bone filling area into threads, bone tissue area and bone density formed out the threads. Variance Analysis was utilized for statistical analysis of the data (p<O,O5). There sults demonstrated statically significant differences for ali parameters toward membrane treated graups (p<O,O5), although, differences were not observed when PRP was utilized( p>O,O5). Within the limits of the present study, it was concluded that PRP do not exert additional effects on bone healing and that guided bone regeneration provides increased bone formation araund dental implants / Doutorado / Periodontia / Doutor em Clínica Odontológica

This paper work deals with properties of metallic biomaterials in terms of their suitability for use as a temporary metal implants. The work focuses on biodegradable materials based on iron and suitable alloying elements, which would create a perfect implant. A part of this work describes procedure of creating biodegradable metallic samples with alloying element Magnesium and measuring the corrosion rates. There are a few theoretical chapters concerning permanent implants, function and composition of human bones, iron and magnesium in human body and biodegradable materials.

Sensitive layers for optical biosensors and protein chips The goal of this thesis was the development of sensitive surfaces for optical affinity biosensors detecting in complex biological media. The practical application of these surface-based technologies has been hampered by protein fouling from biological media, in particular blood plasma, where the vast majority of relevant analytes are present. The work of the thesis was centred in three main foci:  Design and preparation of antifouling and non-fouling surfaces  Evaluation and conceptualisation of their resistance to fouling from blood plasma and serum as well as other biological fluids  Preparation of sensitive layers for detection in complex biological media Three approaches were used to prepare protein resistance surfaces, i) ω-functional self-assembled monolayers (SAM), ii) end-tethered polymers and iii) polymer brushes prepared by surface initiated controlled radical polymerisation. Investigation of proteins in the blood plasma deposits on PEG- based surfaces revealed that some fouling is unavoidable in PEG-based surface modifications. A novel type of non-fouling polymer brushes based on poly[N-(2-hydroxypropyl) methacrylamide] challenged the accepted ideas for the design of protein resistant surfaces. For the first time a...

Lysophosphatidic acid (LPA) influences many physiological processes, such as brain and vascular development. It is associated with several diseases including ovarian cancer, breast cancer, prostate cancer, colorectal cancer, hepatocellular carcinoma, multiple myeloma atherosclerotic diseases, cardiovascular diseases, pulmonary inflammatory diseases and renal diseases. LPA plasma and serum levels have been reported to be important values in diagnosing ovarian cancer and other diseases. However, the extraction and quantification of LPA in plasma are very challenging because of the low physiological concentration and similar structures of LPA to other phospholipids. Many previous studies have not described the separation of LPA from other phospholipids, which may make analyses more challenging than necessary. We developed an SPE extraction method for plasma LPA that can extract LPA at high purity. We also developed an HPLC post-column fluorescence detection method that allows the efficient quantification of LPA. These methods were used in a clinical study for ovarian cancer diagnosis to help validate LPA as a biomarker of ovarian cancer. Moreover, molecular imprinted polymers (MIPs) were designed and synthesized as material for the improved extraction of LPA. Compared to the commercially available materials, the MIP developed shows enhanced selectivity for LPA. The extraction was overall relatively more efficient and less labor-intensive.

In vitro liver models allow the investigation of the cell behavior in disease conditions or in response to changes in the microenvironment. A major challenge in liver tissue engineering is to mimic the tissue-level complexity: besides the selection of suitable biomaterial(s) replacing the extracellular matrix (ECM) and cell sources, the three-dimensional (3D) microarchitecture defined by the fabrication method is a critical factor to achieve functional constructs. In this study, coaxial extrusion-based 3D bioprinting has been applied to develop a liver sinusoid-like model that consists of a core compartment containing pre-vascular structures and a shell compartment containing hepatocytes. The shell ink was composed of alginate and methylcellulose (algMC), dissolved in human fresh frozen plasma. The algMC blend conferred high printing fidelity and stability to the core–shell constructs and the plasma as biologically active component enhanced viability and supported cluster formation and biomarker expression of HepG2 embedded in the shell. For the core, a natural ECM-like ink based on angiogenesis-supporting collagen-fibrin (CF) matrices was developed; the addition of gelatin (G) enabled 3D printing in combination with the plasma-algMC shell ink. Human endothelial cells, laden in the CFG core ink together with human fibroblasts as supportive cells, formed a pre-vascular network in the core in the absence and presence of HepG2 in the shell. The cellular interactions occurring in the triple culture model enhanced the albumin secretion. In conclusion, core–shell bioprinting was shown to be a valuable tool to study cell–cell-interactions and to develop complex tissue-like models.

OBJETIVO El objetivo nuestro proyecto de investigación es demostrar si la presencia de plasma rico en plaquetas (PRP) autólogo, que aporta varios factores de crecimiento en proporciones fisiológicas, en la interfase injerto tendinoso-hueso modifica el proceso de reparación de los tejidos locales en nuestro modelo experimental. MATERIAL Y MÉTODO Diseñamos un estudio de tipo experimental, longitudinal y prospectivo. Diez conejos albinos de Nueva Zelanda son intervenidos en sus 2 extremidades traseras, en una se realiza la técnica Experimental aplicando PRP y la otra sirve de control, sin aplicar PRP . Una vez intervenidos, los animales son divididos en 2 grupos de 5 de forma aleatoria. Un grupo es sacrificado a la 2ª semana y el otro a la 4ª semana postintervención. El área quirúrgica fue estudiada macroscópica, radiográfica, histológica e inmunohistoquímicamente. RESULTADOS El estudio macroscópico y radiográfico de las piezas muestra la presencia de un área de reacción ósea de mayor tamaño en la zona de entrada del tendón en el interior del túnel óseo en el grupo Experimental sacrificado a la 4ª sem. respecto al resto de grupos. Microscópicamente, en ningún corte histológico, tanto de los grupos Control como Experimental, se observa la línea de separación basófila, denominada tidemark190 entre el fibrocartílago mineralizado y el no mineralizado. Si se evidenció la aparición de una mayor cantidad de los elementos tisulares fibrosos, cartilaginosos y osteoides, y un mayor grado de ordenación celular en el fibrocartílago y sustancia osteoide en los grupos Experimentales respecto a sus correspondientes grupos Control. Además se observa la aparición de zonas de anclaje hueso-tendón en dos extremidades del grupo Experimental sacrificado a la 4ª sem., no encontradas en ningún caso Control. En el estudio inmunohistoquímico no apreciamos diferencias en el patrón de distribución del colágeno tipo II entre los distintos grupos, aunque si existe una mayor área de tinción de colágeno tipo II en los grupos Experimentales respecto a sus correspondientes grupos Control, ya que la cantidad de tejido fibrocartilaginoso, en sus variadas formas de presentación, también es mayor en los grupos que recibieron PRP. CONCLUSIONES El análisis de los resultados concluye que macroscópica, radiográfica y microscópicamente, este estudio demuestra que la administración de PRP como fuente de FC afecta al proceso de reparación del autoinjerto tendinoso dentro de un túnel óseo en nuestro modelo experimental. El PRP aceleró la curación, anticipando en el tiempo la aparición de elementos celulares y tisulares propios de fases posteriores del proceso de cicatrización, y además incrementó la cantidad éstos. / EFFECT OF PLATELET RICH PLASMA IN THE BIOLOGIC INCORPORATION OF A TENDON GRAFT IN A BONE TUNNEL Objective: To study the effect of the platelet rich plasma (PRP) in the biological process of tendon healing inside a bone tunnel Material y Methods: We designed an experimental, longitudinal and prospective research study. Ten animals were operated on their back legs (one as Experimental group and the other as Control group). In the Experimental group the tendon of the internal gastrocnemius muscle was cut, infiltrated with PRP, placed in a tibial bone tunnel filled with PRP, and finally, fixed by a bioabsorbable screw. The same procedure was practiced in the Control group without the use of PRP. Five rabbits were sacrificed on the second week and five on the fourth week after surgery. The legs were evaluated macroscopic, radiographic, histologic and immunohistochemically. Results: The macroscopic and radiographic study of the pieces shows the presence of a larger bone reaction area in the entrance of the tendon within the bone tunnel in the Experimental group sacrificed on the fourth week compared to other groups. Microscopically, the "tidemark" isn’t observed between mineralized and unmineralized fibrocartilage in any group . The Experimental group presents a statistically significant greater amount of chondroid tissue, osteoid tissue and trabecular bone, both the second and fourth week. We observe continuity zones between tendinous fibers and bone in some cases of the Experimental group on the fourth week . Immunohistochemically, no appreciable differences in the distribution pattern of type II collagen between the groups could be seen, although there is a greater area of staining in the Experimental group compared to their corresponding Control group Conclusion: The analysis of results and assessment of the comparison established between the research groups concludes that macroscopic, radiographic and microscopically, this study demonstrates that administration of PRP affects the repair process of tendon autograft in a bone tunnel in our experimental model. The PRP accelerated the healing time anticipating the emergence of cellular and tissue elements characteristic of later stages of the healing process, and also increased the amount of them.