Effects of GnRHa active immunity on FSHR expression and uterine development in prepuberty and non cyclic ewes

This study explored the effects of GnRH agonist (GnRHa) immunity on expression of FSHR mRNA in pituitary and FSHR protein in uteri, and also confirmed its efficacy on uterine development. 42 prepuberty and non cyclic ewes were assigned to 6 experimental groups (EG) during anestrus season. Animals in EG-I, EG-II and EG-III were subcutaneously injected with 200, 300 and 400 μg alarelin antigens (day 0 and 14). Animals in EG-IV and EG-V were subcutaneously injected with 200 and 300 μg alarelin antigen (day 0, 7, 14 and 21). Uterine FSHR protein expression was detected using Western-blotting. RT-PCR was implemented to measure expression of pituitary FSHR mRNA on day 70 after the immunity. Compared to the CG, pituitary FSHR mRNA levels reduced by 58%, 88% and 91% (P<0.01) in EG-I, EG-II and EG-III. FSHR mRNA in EG-IV and EG-V reduced by 64.29% (P<0.05) and 10.11% compared to EG-I and EG-II. Expression levels of uterine FSHR protein in EG-III and EG-V were higher than that in CG. The uterine glands, mitochondria and mitochondrial crista decreased, and the glandular cavity reduced, also the microvilli shortened. Uterine horn weights in EG-I, EG-II and EG-III reduced by 4.66%, 10.20% and 16.63%, respectively. Uterine wall thickness (UWT) in EG-I, EG-II and EG-III reduced by 1.41%, 5.84% and 8.75% (P 0.05). The endometrial epithelium thickness (EET) in EG-I, EG-II and EG-III decreased 2.70%, 8.87% and 19.15%. The positive correlations between uterine horn weights and UWT, EET and FSHR were calculated.