Study On The Follicles Development And Expression Of α/β Estrogen Receptors And Their Regulations In Ovaires Of Prepubertal Mice And Goats

The animal’s well-developed oocytes by in vitro maturation, fertilization, embryo cultureare available to complete the descendants of individuals. A large numbers of comparativestudies confirm that prepubertal mammals such as mice, pigs, goats and cattle et al, oocytesdevelopmental competence after in vitro maturation and fertilization is very low, even is notthe formation of embryonic. This shows that the prepubertal oocytes development defects, thecause or mechanism of this defect is unclear. Many techniches or methods including differentculture mediums and many stimuli have been conducted to improve prepubertal follicledevelopmental competence. It has not achieved the desired effect, which is obviouslyrestricting the application of prepubertal female animal oocytes and is key scientific issuesand technical problems in the embryo transferthe engineering and animal cloning.In order toprove the estrogen receptor has important biological significance of follicle development,using mouse, Yimeng black goat, Boer goat, designed a series of scientific experiments,hoping to solve the key scientific questions, to fill at home and abroad the research gaps, andexplore ways and means to improve the potential of follicular development through theestrogen receptor regulatory pathways. This thesis includes3independent parts as following.Experiment1Comparison of estrogen secretion and its receptors expression in follicle ovain prepubertal and pubertal miceObjective: To observe the correlation between the distribution and expression of estrogenreceptors (ERs) and the developmental competence deficiencies of follicle ova in prepubertalmammal animals. Methods: Estrogen concentrations in blood of prepubertal and pubertalmice were detected with radioimmunoassay(RIA) and the distribution and expression of α-、β-ERs in ova were analyzed with serial tissue sections and immunohistoehemistry. Results:Data indicate that estrogen concentrations are dramatically lower in prepubertal ages than inpuberty ages and they are increasing with aging. ERα、βs are expressed at different degrees inovary cells, especially in ovarian granulose cells. But ERβs are distributed much more,whether in prepubertal ovary cells or in puberty ovary cells, than ERαs. ERαs expressed incells are less significantly in prepubertal mice ovaries than in puberty ovaries. Conclusion: It can be concluded that estrogen concentrations in blood and the less expression of α-ERs inovary cells are dramatically difference in prepubertal and pubertal mice, which can interpretthe low developmental competence deficiencies of prepubertal follicles ova.Experiment2Comparative study of the folliole development and the mRNA expression ofestrogen receptors in prepubertal and pubertal goatsTo compared the follicle development and the mRNA expression of α-/β-estrogenreceptors(ERα、ERβ) in prepubertal goats with that in puberty ovaries obtained from Boerand Yimeng Black Goats with different ages were observed with serial tissue sections and HEstaining methods and the mRNA expression of ERα、ERβ in ovary follioles were detectedwith Fluorescence quantitative RT-PCT assays. The results indicate that the numbers ofPrimordial follicle and Primary follicle in prepubertal goats are more than in puberty, but withpoor development and little size and granule cells, and the numbers of mature follicle is lessin prepubertal goats’ ovaries. The mRNA expressions of ERα/ERβ in prepubertal ovariesboth are less than in puberty ones and the mRNA expression of ERα, whether in prepubertyor in puberty, is less that of ERβ. It can be deduced that the follicle development in goatsdepends, directly or indirectly, on the expression of ERα/ERβ and the low development offollicle oocytes in prepuberty probablely resulted from the less ERα/ERβ in ovaryfollicles.Experiment3Effect of E2/FSH/LH on the development of follicle and the expression of ERα/ERβin prepuberty mice20-day-age mice were divided into four groups and the mice in three treated groupsinjected peritoneal with E2or FSH or LH at physiological dose, respectively; the controlmice were injected with equal PBS liquid, twice per mice and interval3days per time. Thefollicle development were observed and estrogen concentrations in blood of prepuberty andpuberty mice were detected with radioimmunoassay(RIA) and the distribution and expressionof ERα、βs in ovary follicles were analysised with serial tissue sections andimmunohistoehemistry. Data indicate that E2/FSH/LH increase the numbers of follicles andgranular cells with the expression of ER α/β, and FSH/LH promote the development ofdominant follicles and early ovulation and the expression of ERα in follicles; FSH and LHboth increase the secretion of endogenous estrogen, but extrogenous E2dose not. It can be concluded that extrogenous E2/FSH/LH can regulate the development of follicles andincrease the expression of ERα/β in prepuberty mice.