We review morphological features of the amniote egg and embryos in a comparative phylogenetic framework, including all major clades of extant vertebrates. We discuss 40 characters that are relevant for an analysis of the evolutionary history of the vertebrate egg. Special attention is given to the morphology of the cellular yolk sac, the eggshell, and extraembryonic membranes. Many features that are typically assigned to amniotes, such as a large yolk sac, delayed egg deposition, and terrestrial reproduction have evolved independently and convergently in numerous clades of vertebrates. We use phylogenetic character mapping and ancestral character state reconstruction as tools to recognize sequence, order, and patterns of morphological evolution and deduce a hypothesis of the evolutionary history of the amniote egg. Besides amnion and chorioallantois, amniotes ancestrally possess copulatory organs (secondarily reduced in most birds), internal fertilization, and delayed deposition of eggs that contain an embryo in the primitive streak or early somite stage. Except for the amnion, chorioallantois, and amniote type of eggshell, these features evolved convergently in almost all major clades of aquatic vertebrates possibly in response to selective factors such as egg predation, hostile environmental conditions for egg development, or to adjust hatching of young to favorable season. A functionally important feature of the amnion membrane is its myogenic contractility that moves the (early) embryo and prevents adhering of the growing embryo to extraembryonic materials. This function of the amnion membrane and the liquid-filled amnion cavity may have evolved under the requirements of delayed deposition of eggs that contain developing embryos. The chorioallantois is a temporary embryonic exchange organ that supports embryonic development. A possible evolutionary scenario is that the amniote egg presents an exaptation that paved the evolutionary pathway for reproduction on land. As shown by numerous examples from anamniotes, reproduction on land has occurred multiple times among vertebrates—the amniote egg presenting one “solution” that enabled the conquest of land for reproduction.

Development of the yolk sac of squamate reptiles (lizards and snakes) differs from other amniote lineages in the pattern of growth of extraembryonic mesoderm, which produces a cavity, the yolk cleft, within the yolk. The structure of the yolk cleft and the accompanying isolated yolk mass influence development of the allantois and chorioallantoic membrane. The yolk cleft of viviparous species of the Eugongylus group of scincid lizards is the foundation for an elaborate yolk sac placenta; development of the yolk cleft of oviparous species has not been studied. We used light microscopy to describe the yolk sac and chorioallantoic membrane in a developmental series of an oviparous member of this species group, Oligosoma lichenigerum. Topology of the extraembryonic membranes of late stage embryos differs from viviparous species as a result of differences in development of the yolk sac. The chorioallantoic membrane encircles the egg of O. lichenigerum but is confined to the embryonic hemisphere of the egg in viviparous species. Early development of the yolk cleft is similar for both modes of parity, but in contrast to viviparous species, the yolk cleft of O. lichenigerum is transformed into a tube-like structure, which fills with cells. The yolk cleft originates as extraembryonic mesoderm is diverted from the periphery of the egg into the yolk sac cavity. As a result, a bilaminar omphalopleure persists over the abembryonic surface of the yolk. The bilaminar omphalopleure is ultimately displaced by intrusion of allantoic mesoderm between ectodermal and endodermal layers. The resulting chorioallantoic membrane has a similar structure but different developmental history to the chorioallantoic membrane of the embryonic hemisphere of the egg.

Embryos of oviparous Reptilia (=turtles, lepidosaurs, crocodilians and birds) extract calcium for growth and development from reserves in the yolk and eggshell. Yolk provides most of the calcium to embryos of lizards and snakes. In contrast, the eggshell supplies most of the calcium for embryonic development of turtles, crocodilians and birds. The yolk sac and chorioallantoic membrane of birds recover and transport calcium from the yolk and eggshell and homologous membranes of squamates (lizards and snakes) probably transport calcium from these two sources as well. We studied calcium mobilization by embryos of the snake Pantherophis guttatus during the interval of greatest embryonic growth and found that the pattern of calcium transfer was similar to other snakes. Calcium recovery from the yolk is relatively low until the penultimate embryonic stage. Calcium removal from the eggshell begins during the same embryonic stage and total eggshell calcium drops in each of the final 2 weeks prior to hatching. The eggshell supplies 28% of the calcium of hatchlings. The timing of calcium transport from the yolk and eggshell is coincident with the timing of growth of the yolk sac and chorioallantoic membrane and expression of the calcium binding protein, calbindin-D28K, in these tissues as reported in previous studies. In the context of earlier work, our findings suggest that the timing and mechanism of calcium transport from the yolk sac of P. guttatus is similar to birds, but that both the timing and mechanism of calcium transport by the chorioallantoic membrane differs. Based on the coincident timing of eggshell calcium loss and embryonic calcium accumulation, we also conclude that recovery of eggshell calcium in P. guttatus is regulated by the embryo.

In 1926, the German biologist Johanna (Hanni) Hrabowski published a study of the morphology and development of the fetal placenta in lizards that has proven to be of historical importance. Her anatomical descriptions and interpretations identified developmental patterns that differ from other amniotes – features now recognized as unique attributes of squamate (lizards and snakes) development. Her 1926 monograph presented the first histological comparison of fetal membranes in closely-related oviparous and viviparous reptiles, thereby establishing a comparative framework for understanding placental specializations for viviparity. Hrabowski reported that yolk sac development did not differ between oviparous and viviparous species. The novel, shared components of yolk sac development she identified are now recognized as the foundation for the unique yolk sac placenta of reptiles, the omphaloplacenta. In addition, Hrabowski's extensive ontogenetic sampling and the detail and accuracy of her anatomical descriptions set high standards for subsequent studies of comparative evolutionary embryology.

Average global ocean temperatures and the frequency and intensity of marine heat waves have been increasing over the last century. Temperature plays a critical role in defining the geographical range of the majority of marine species. Some species may respond to ocean warming trends by shifting their latitudinal and depth ranges, while others may be able to cope with changes in temperature through phenotypic plasticity and local adaptations. If a species is unable to shift its distribution or has limited thermal plasticity, it may face severe population declines or local extinction. Therefore, describing thermal tolerance limits is a useful tool for predicting how a given species will respond to ocean warming. Due to its commercial importance, sablefish (Anoplopoma fimbria) is a fish species of particular interest in British Columbia. Sablefish are semi-demersal and spawn along the continental slopes of the Pacific coast from California to Alaska. Their various life history stages occupy different depth strata and thus experience substantially different environments with respect to temperature (as well as salinity, oxygen, etc.). Adult sablefish spawn at depths that exceed 300 m and embryos sink to depths of ~1,000 m after fertilization. Embryos hatch into yolk-sac larvae until they become mobile at the post-yolk-sac larvae stage. The latter migrate to near-surface waters (<3 m) at which temperatures are approximately 12-15°C in the late spring. Heart rate is a temperature-dependent performance measure and has been used to gain insight into the thermal tolerance of many adult fishes. However, few studies have used this approach with the early life stages of fishes such as embryos and yolk-sac larvae (YSL). The purpose of this study was to assess whether sablefish embryos and YSL have the potential for cardiac acclimation by examining changes in their thermal tolerance limits when incubated at temperatures outside of what they experience in a natural setting (~5°C). Cardiac performance was assessed during an acute temperature challenge from 2.0° to 12.0°C in increments of 1.0°C (at a rate of 1°C 40 min-1) for individuals incubated at 3.0°C, 5.0°C (control), and 7.0°C. Embryos were video recorded at each 1.0°C increment and videos were viewed at a later date to determine heart rate at each temperature. This study attempted to use temperature breakpoint analysis, commonly used in studies of adults, on these early life stages to assess cardiac performance. It was hypothesized that sablefish embryos and yolk-sac larvae incubated at warmer temperatures would have a higher thermal tolerance than sablefish embryos and YSL incubated at colder temperatures, as seen in other fish species. There was some degree of thermal compensation of cardiac function with temperature in sablefish embryos and YSL as mean heart rate increased with incubation temperature throughout acute warming. YSL had consistently higher mean heart rate values at any given temperature of the acute temperature challenge when compared to embryos incubated at the same temperature. TAR is the temperature at which the heart first becomes arrhythmic is considered a sub-lethal index because the organism is expected to experience cardiac collapse soon after. TAR was reached for 100% of embryos incubated at 3.0°C at an average temperature of 8.6 ± 1.0°C. In contrast, only 18% and 33% of embryos incubated at 5.0° and 7.0°C exhibited arrhythmia (mean TAR were 9.0 ± 3.0 and 8.5± 1.5°C, respectively). The lower thermal limit for embryos incubated at 7.0°C was likely near 1.0°C, which was determined during preliminary testing. Neither the upper or lower limits were reached for YSL during the acute temperature challenge. No mortalities were observed during any acute temperature challenges. Overall percent mortality throughout the entirety of the experiment could not be determined due to limitations in the experimental setup and reduced staff working on this project due to COVID-19 safety protocols. This study is also the first to investigate whether transporting sablefish embryos from a hatchery to a research facility at different stages of development had an effect on their cardiac performance during acute warming. Embryos were transported in a cooler from the sablefish hatchery on Salt Spring Island to UVic via ferry and vehicular transport. Time of transportation did not significantly change the temperature at which heart rate reaches its maximum or TAR. There was also consistent overlap in mean heart rate ± standard error at each temperature of the acute temperature challenge between these two groups. Therefore, there appears to be no indication that transportation affected the heart rate response of sablefish embryos when incubated at the same temperature. However, future studies may want to confirm this by identifying and comparing other breakpoint temperatures that characterize physiological performance. Determining whether transportation has effects on cardiac performance may be of interest to other researchers who need to transport fish embryos from the field to the laboratory. Heart rate measurements during an acute temperature challenge of sablefish embryos and yolk-sac larvae (YSL) incubated at various temperatures provided initial insight to their overall success in a warming climate. Currently, it is projected that waters at depths of 1,000 m will warm on average by less than a degree by the end of the 21st century. The results of this study suggest that the early life stages of sablefish may not be exposed to critical temperatures in the near future, but future impacts on overall physiological decline remain unknown. The novel data presented here lay the groundwork for future researchers to continue to characterize the thermal tolerances of the early life stages of sablefish, and the likely response of this important species to ocean warming. / Graduate

The small intestine and yolk sac (YS) are important organs for nutrient absorption and innate immunity in chickens during the post-hatch or prehatch periods. These organs share a similar structure of epithelial cell-lined villi with tight junctions between adjacent cells. Probiotics have been reported to improve chicken growth performance and gut health including promotion of intestinal morphology. However, there are few studies that show the effect of probiotics on ontogeny of intestinal epithelial cells and antimicrobial peptides, or intestinal integrity in young healthy chicks. Heat stress during incubation was shown to increase mortality and decrease hatchability of chicks, while no studies have investigated the effect of heat stress on the integrity of the YS, which might be related to hatching performance. There were four studies conducted in this research: 1) a comparison of the effect of two probiotics on the ontogeny of small intestinal epithelial cells in young chicks; 2) the effect of two probiotics on mRNA abundance of tight junction proteins in the small intestine of young chicks; 3) the effect of high incubation temperature on mRNA abundance of tight junction proteins in the YS of broiler embryos; and 4) comparison of avian defense peptide mRNA abundance in the YS of broilers and layers. In study 1, Probiotics transiently decreased body weight gain (BWG) from day 2 to day 4, but did not affect body weight (BW) from day 2 to day 8, and small intestinal weight and intestinal morphology from day 2 to day 6. Probiotics did not affect marker gene expression of intestinal stem cells (Olfm4) and goblet cells (Muc2) in all small intestinal segments, but did increase expression of a marker gene of proliferating cells (Ki67), and decreased an antimicrobial peptide (liver-enriched antimicrobial peptide 2, LEAP2) in the jejunum at day 4. Probiotic 1 decreased PepT1, a marker of enterocytes in the duodenum at day 4. These results suggest that probiotics did not improve growth performance and intestinal morphology in young healthy chicks, but temporarily promoted intestinal epithelial cell proliferation and decreased LEAP2 antimicrobial peptide expression in the jejunum. In situ hybridization (ISH) showed that Ki67+ proliferating cells were mainly located in the crypt region and the blood vessels of villi. In study 2, Probiotic supplementation to newly hatched chicks for less than one week did not affect mRNA abundance of the tight junction proteins in the small intestine. Occludin (OCLN) mRNA, which was detected by ISH to be expressed in intestinal epithelial cells in both the villus and crypt regions, was greater in the duodenum of female chicks than males. In study 3, high incubation temperature starting from embryonic day 12 (E12) affected mRNA abundance of the tight junction proteins in the YS, including increased zonula occluden 1 (ZO1) at E13, increased junctional adhesion molecule A (JAMA) and heat shock protein 90 (HSP90) at E17, but decreased tight junction protein JAMA at E19 and OCLN at day of hatch (DOH). These results showed that the YS tight junction proteins were increased by short term heat exposure but decreased by long term heat exposure. In study 4, the expression of avian β defensin 10 (AvBD10), CATHs and toll-like receptors in the YS was examined. Toll-like receptors were highly expressed in the YS at early incubation stages (E7), while CATHs showed a peak expression from E9 to E13, which was similar to the expression pattern of AvBD10. CATHs and AvBD10 mRNA temporal expression patterns were similar in broilers and layers, while their expression levels were different. Layers, especially brown layers, had greater mRNA abundance for antimicrobial peptides such as AvBD10, CATH1, and CATH2 in the YS. These results demonstrate that the antimicrobial peptide temporal expression patterns in the YS are not affected by breed, but their expression levels are affected by breed. In summary, the small intestine and the YS are essential for nutrient uptake, innate immunity, and maintenance of integrity. The ontogeny of intestinal epithelial cells, such as proliferating cells can be modulated by probiotic supplementation. Similar to the small intestine, the YS can also express tight junction proteins, which can be affected by high incubation temperature. Antimicrobial peptide expression in the intestine of healthy young chicks is also transiently decreased by probiotic supplements. Avian defensin and cathelicidin expression patterns in the YS were not affected by breed. / Doctor of Philosophy / The small intestine and yolk sac are important organs for nutrient absorption in hatched chicks or embryonic chicks. These organs also serve as a barrier to prevent pathogens from entering the blood circulation. Intestinal epithelial cells along the villi renew rapidly by proliferation and differentiation. In this research, probiotics which are also known as direct fed microbials temporarily increased expression of the proliferating cell marker Ki67 in the jejunum of healthy young chicks, which suggests that probiotics promote intestinal epithelial cell proliferation. However, probiotics transiently decreased expression of an antimicrobial peptide, which may reduce immune protection in the gut. The yolk sac can also express tight junction proteins. The expression of tight junction proteins was affected by elevated incubation temperature in broiler embryos, which might be related to low hatchability of eggs exposed to heat stress. Avian defense peptides and pathogen recognition receptors were expressed in the YS, which implied that the yolk sac contained an innate immune function. The expression pattern of avian defense peptides was affected by breed (broilers and layers), while the expression level of avian defense peptides was greater in layers than broilers. In summary, the small intestine and the yolk sac are multifunctional organs. Their cell composition, structural integrity, and secretion of antimicrobial peptides can be affected by environmental factors, such as probiotic supplementation or high incubation temperature.

The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler's life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick. / Master of Science / The incubation period is crucial for development and overall quality of a chick. The selection for fast growing broilers has allowed the birds to reach market weight at a faster rate making the incubation period a larger portion of a broiler’s life. A faster growth rate can lead to the release of more metabolic heat inside of the egg toward the second half of incubation because the embryo shifts to a homeothermic state. More heat being released into the incubator can cause the incubation temperature to rise if the incubator is not electronically regulated or cannot be ventilated properly due to malfunction. A high incubation temperature can impact the hatchability, growth, and development of the chick. This thesis provides a more in-depth analysis of the effects of high incubation temperature (37.5°C versus 39.5°C) on the developing small intestine and yolk sac, which provide the chick with nutrients posthatch and during embryogenesis. Studying these organs and mechanisms occurring during this time could potentially indicate why chicks from eggs subjected to a higher incubation temperature are not developing and growing properly. Chicks from eggs incubated at a higher temperature had lower body weights, lower hatchability and lower villus height in the duodenum, jejunum, and ileum. There were also differences seen in the depth of the crypt, which is the site for stem cells. Chicks from eggs incubated at a higher temperature had a lower crypt depth in the duodenum and jejunum. There was no difference in the expression of the intestinal stem cell marker olfactomedin 4 (Olfm4) and mucin 2, which is secreted by goblet cells and forms mucus. In the yolk sac, heat shock proteins (HSP) 70 and 90 were elevated at embryonic day 15, and HSP90 still remained elevated at embryonic day 17. Chicks from eggs incubated at a higher temperature showed greater expression of peptide transporter 1 and avian beta-defensin 10 mRNA at embryonic day 13. Even though small intestinal morphology was impacted early posthatch and expression of genes in the yolk sac were elevated at embryonic day 13, there does not seem to be a long-lasting effect on the development of the small intestine or the yolk sac. It is still important to study the impact of the incubation environment to understand the development and growth of the chicks and how different incubation factors can impact the overall hatchability and health of the chick.

O saco vitelínico é uma das membranas embrionárias que desempenham um papel importante para a sobrevivência inicial do embrião em muitas espécies de mamíferos, além de produzir proteínas necessárias para o desenvolvimento do mesmo. Foram coletados 17 embriões bovinos, em diferentes períodos gestacionais afim de identificar as proteínas alfafetoproteína, alfa- 1 antitripsina e transferrina, presentes no saco vitelínico destes,para tanto realizou-se a técnica de Western Blot com eletroforese em gel de poliacrilamida, SDS-PAGE a 6%. Os géis, após a corrida, foram corados com Comassie blue, e as membranas de nitrocelulose, após a transferência, com Ponceau. Utilizaram-se os anticorpos monoclonal para alfafetoproteína anti-camundongo, monoclonal, receptpr de transferrin anti-camundongo IgG1, e policlonal para alfa- 1 antitripsina anti-coelho como anticorpos primário e conjugado para peroxidase e fosfatase como secundários. A revelação foi do tipo colorimétrica-fosfatase alcalina e por ECL. O saco vitelínico apresentou-se bem desenvolvido até os 50 dias de gestação, onde, a partir desse período o processo de involução está bem caracterizado Em algumas amostras do saco vitelínico detectamos a presença da alfafetoproteina, alfa-1 antitripsina e da transferrina, porém em algumas amostras as bandas estavam fracas, mostrando assim, que os anticorpos reagem com as proteínas bovinas. O fato de aparecerem bandas fracas pode estar relacionado a uma fraca reação cruzada por se tratar de um anticorpo não específico. / In many species of mammals, the yolk sac is one of the embrionary membranes that plays an important role in the embryo´s initial survival, as well as, in the manufacturing of the necessary proteins for its development. In order to identify the proteins: alfafetoprotein, alfa 1 - antitrypsin, and transferrin present in the cow´s embryo´s yolk sac, 17 bovine embryos were collected in different pregnancy periods. This procedure was performed by Western Blot Technique with a polyacrylamide gel electrophoresis, SDS-PAGE, at 6%. Gels following the electrophoresis, where tainted with Comassie blue, and the membranes of Nitrocellulose, following their transference (the proteins that were present in the gel go to the membrane), with Ponceau. Monoclonal Antibody mouse anti human &alpha;-fetoprotein, alphafetoprotein mouse monoclonal antibody, transferrin receptor mouse IgG1, and rabbit polyclonal to alpha 1 antitrypsin were used as primary antibodies, and Peroxidase labelled antimouse e Peroxidase labelled antirabbit e anti-mouse IgG- Alkaline Fosfatase as secundary ones. The membrane´s revelation was of the alcaline fosfatase colormetric type and by ECL. The yolk sac was presented well developed until the 50 days of gestation, where to break of this period the involution process well it is characterized. In some of the yolk sac samples we detected the presence of alfafetoprotein, alfa 1- antitrypsin, and transferrin, however, the bands in some specimens (samples) were weak, demonstrating that the antibodies react with the bovine proteins. The fact that weak bands appeared might be related to a weak cross reaction since we are dealing with a non specific antibody.

O cão é um excelente modelo pré-clínico para o estudo de doenças, testes farmacológicos e novas terapias para futura aplicação em humanos. Desta forma, estudamos o modelo canino como fonte de células tronco de anexos fetais, o líquido amniótico, alantóide e conteúdo vitelino. Uma vez que hoje, as células tronco apresentam uma esperança na cura de diversas doenças tanto nos cães, como no ser humano. Sendo assim, caracterizamos e estudamos o potencial de diferenciação dessas células, isoladas após a técnica de ovário salpingo histerectomia, de cadelas em campanhas de castração. Após o isolamento e a caracterização, somente foi estabelecida a cultura do líquido amniótico e alantóide. Para caracterizar as células, isoladas no intuito de comprovar que são células tronco verdadeiras, os seguintes Imunomarcadores foram usados, vimentina, nestina, citoqueratina-18 e oct-4, sendo os três primeiros positivos para células do líquido amniótico e alantóide. Induzimos a diferenciação dessas células para osso, cartilagem e gordura, utilizando protocolos previamente estabelecidos. As células tronco do líquido amniótico limitaram-se à diferenciação condrogênica e osteogênica enquanto que as células tronco do alantóide, limitaram-se a diferenciação condrogênica. Ao mesmo tempo, ambos os tipos celulares, não prosseguiram à diferenciação adipogênica. Surpreendentemente, o meio de diferenciação para gordura, induziu a mudança morfológica nestas células que passaram a apresentar a morfologia típica de células neuronais. Podemos concluir que provavelmente para diferenciação adipogênica, é preciso desenvolver outro meio de cultura, por outro lado, esse resultado sugere que devemos explorar o potencial neurogênico desses tipos celulares. / The dog is an excellent preclinical model for the study of diseases, pharmacological tests and new therapies for future application in humans. Thus, we studied the canine model as a source of stem cells from fetal membranes, amniotic fluid, allantois and fluid yolk. Since today, stem cells have a hope in curing various diseases in both dogs and humans. Therefore, we characterize and study the differentiation potential of these cells, isolated after the technique of ovarian salpingo hysterectomy. After the isolation and characterization, was only established the culture of amniotic and allantois fluid. To characterize the cells isolated in order to demonstrate that they are true stem cells, the following were used antibodies, vimentin, nestin, cytokeratin-18 and oct-4. The cells were reactive positively to vimentin, nestin, cytokeratin. We induced the differentiation of these cells osteogenic, chondrogenic, adipogenic, using previously established protocols. Stem cells from amniotic fluid were restricted to chondrogenic and osteogenic differentiation while the stem cells of the allantois, limited to chondrogenic differentiation. At the same time, both cell types, were not able to adipogenic differentiation. Surprisingly, the means of adipogenic differentiation, induced the typical morphology of neuronal cells. We can conclude that probably for adipogenic differentiation, we must develop other culture media, on the other hand, this result suggests that we should explore the neurogenic potential these cell types.

Atualmente a terapia com células-tronco têm sido uma ferramenta útil na medicina regenerativa com alto potencial terapêutico devido à capacidade de auto renovação e diferenciação destas células. Nos últimos anos a ortopedia vem procurando novos métodos para um tratamento que obtenha como efeito a reparação de defeitos articulares de forma mais efetiva e sem procedimentos invasivos. Por isso, muitos estudos envolvendo terapia celular com objetivo de melhorar a reparação articular estão sendo realizados. O objetivo deste estudo foi avaliar a terapia com células-tronco de saco vitelino e de polpa dentária canina em cães com displasia coxofemoral mediante três aplicações celulares (dia 0, 30 e 60, e um controle dia 90). Para a avaliação dos animais tratados foi instituído um grupo controle para cada tipo celular testado, sendo avaliado o escore de claudicação, escore de atrofia muscular, questionário de qualidade de vida, avaliação radiográfica, análise do líquido sinovial e hemograma. Os resultados obtidos demonstraram não haver uma diferença estatística significante quando comparado os animais dos grupos tratamentos e controle. Quando comparado os animais dos grupos tratamento houve uma diferença estatística significante para os animais tratados com células-tronco de saco vitelino em relação aos animais tratados com células-tronco de polpa dentária. O tratamento com células de saco vitelino mostrou melhores resultados nos testes de Ortolani. / Currently, stem cell therapy have been a useful tool in regenerative medicine with high therapeutic potential due to the capacity for self renewal and differentiation of these cells. In recent years, orthopedics has been seeking new methods of treatment to obtain the effect of repair of articular defects more effectively and without invasive procedures. Therefore, many studies involving cell therapy in order to improve the repair articular are being conducted. The aim of this study was to evaluate the therapy with stem cells from the yolk sac and canine dental pulp in dogs with hip dysplasia by three mobile applications (day 0, 30 and 60, and one day control 90). For the evaluation of the treated animals was set up a control group for each cell type tested, and rated the lameness score, muscular atrophy score, a questionnaire about quality of life, radiographic evaluation, synovial fluidanalysis and blood count. The results showed that there was no statistically significant difference when compared animal treatment and control groups. Comparing the animals, treatment groups showed a statistically significant difference for the animals treated with stem cells from the yolk sac for the animals treated with stem cells from dental pulp. Treatment with yolk sac cells showed better results in Ortolani tests.