Studies On Development And Expression Of Estrogen Receptor Alpha (ERα) MRNA,Progestrogen Receptor (PR) MRNA In Femail Beagle's Reproduction Organs

Beagle belong to the animal with single estrus but a relative long dioestrus. This special reproduction characteristic restrains the researches based on dogs. Dog's reproduction characteristic research is theoretically helpful to understand its reproductive physiology thoroughly, also for enhances its reproductive capacity to lay the rationale.Based on the study of Beagle's general reproductive physiological characteristics ,we use methods of histology and in situ hybridization to study the the patterns of Beagle's genital development and the expression of hormone receptors. the main results are as follows.1.The oestrus cycle of female dogs is 230-250d,they may estrus all the year, but has certain differences during the season.the pregnancy rate is high 9-11days after mating , the average pregnancy time is 62.19 days; each litter size averaged 5.30; the ratio of male and female for young dogs is 0.98:1; weanling survival rate is 81.10% .2.The same sections of ovary,uterus and oviduct are collected from birth to PNM 3,6,9,12,15,18 and made paraffin slices, and then made pictures via dyeing .From ovarian tissue slices, we can find that ovarian cortex sections have large numbers of primordial follicles, and granulosa cell rank at the surrounding of the oocytes. With the age increasing, primary,secondary follicles gradually appear,and granulose cells become thicker, the volume of follicles become bigger. For uterus, we find that endometrial gland of Beagle bitches is little in the volume, synchronously small in quantity, and stroma is also few. Between PNMs 3 to 18,the endometrial gland continuously develops and proliferates and become bigger gradually in volume, and more and more in quantity. At the same time, the stroma becomes denser. For oviduct , it had formed primary mucosal folds 9th month ago,and almost full of mucosa lined columnar ciliated and non-ciliated wedge cell.3.Blood samples are collected from birth to PNM 3,6,9,12,15,18 and different oestrus cycle.Concentrations of E₂ and P₄ in serum are measured previously by radioimmunoassay, and evaluate their changes. The hormonal concentrations of E₂ is low at birth, and increase after birth and come up to the highest level in 12th month and then decline . The hormonal concentrations of P4 is 0 at birth, and increase after birth and come up to the highest level in 12th month. From third month to the 18th month, E2 maintaining its level at about 20 pg/ml while P4 remaining at a lower level ( <0.8 ng/ml). During oestrus cycle, The hormonal concentrations of E₂ remain in a high level; the P₄ has a upward trend from first day to ninths, and reach the peak then decline.4.Estrogen receptor mRNA expression abundance in the reproductive tissues were investigated by in stiu hybridization histochemistry(ISHH).Results of image manipulation analysis system indicated that ER mRNA almost are not detected at birth in the ovary; ER mRNA expression increased from PNMs 3 to 9, and then declined slightly; postive staining was mainly detected in primordial follicles, primary follicles and secondary follicles, thicker in big follicles than in small follicles; During oestrus cycle, expression of ERαmRNA remained high during the whole oestrus cycle .In uterus, postive intensity of ER mRNA had the significant correlations with PNMs, and ERαmRNA was mainly detected in endometrium gland and lesser in stroma. In estrus cycle, ERαmRNA expression showed a downward trend. ERαmRNA was detected mainly in the pituitary gland cells. ERαmRNA almost are not detected at birth, with the increase of age, ERαmRNA has been maintained at a higher level; in the estrous cycle, ERαmRNA expression showed a downward trend.5.Positive signals for PR were limited exclusively to surface of epithelial cells,granulosa cells,antral follicles and preovulatory follicles, epicardial cells, endometrial cells, luteal cells and stromal cells. PRmRNA almost are not detected at birth, between 3-18 months old, the positive rate is showing a growth trend; positive signals for PR increasing during proestrus and then declined. PRmRNA positive spots mainly located in the uterine gland cells, rare in the matrix and smooth muscle cells. PRmRNA positive spots mainly located also in the pituitary gland cells. with the increase of age, PRmRNA positive spots in third and sixth were high, then decreased. PRmRNA in the estrous cycle has been kept at a lower level.The first uses the way of in situ hybridization (ISH) method to detect ERαand PR mRNA relative expression abundance in the reproductive tissues of Beagle. On the other hand, the study explains their relativities between sex hormonal concentration in plasma and morphopoiesis of reproductive tissues and ERαand PR mRNA expression abundance. To further explore ER and PR gene transcription and translation differences in the level of reproductive performance lay the foundation for the relationship.