Histological Differences in Reproductive Organs and Expression Level Differences of AR and INHA Genes in Male Tibetan Sheep at Different Altitudes

ZHOU Na; GAO Rong; WANG Xinrong

doi:10.15933/j.cnki.1004-3268.2025.05.015

Abstract：To explore the adaptability of Tibetan sheep to high altitude and low oxygen environment,two groups of adult male Tibetan sheep at high altitude(3 500 m)and low altitude(2 200 m)were studied as research objects,paraffin sections,H.E.staining,RT-qPCR,and Western blot were used to compare the histomorphological differences in testicle,epididymis(caput epididymis,corpus epididymis,cauda epididymis),deferens,and the tissue expression level of androgen receptors(AR)and inhibin α(INHA)genes in the reproductive organs of Tibetan sheep at different altitudes.The results showed that compared with low altitude,the seminiferous tubules diameter,seminiferous epithelium thickness,sperm cells diameter,the cross-sectional area of seminiferous tubules and the number of sertoli cells in the testicle of Tibetan sheep at high altitude were significantly decreased,while the spermatogonia epithelium thickness and primary spermatocytes diameter were significantly increased.The internal and external diameters of the epididymal lumen were significantly decreased and the cilia were generally shorter,while the lumen diameter of the deferens increased significantly and the smooth muscle thickness was thinner.Tibetan sheep could promote spermatogenesis and maturation by enhancing the transcriptional regulation of AR gene in corpus epididymis and cauda epididymis and the expression of AR protein in testicle,corpus epididymis,cauda epididymis and deferens in high altitude environment.Compared with Tibetan sheep at low altitude,the expression of INHA gene in caput epididymis,cauda epididymis,and deferens of Tibetan sheep at high altitude was significantly decreased,and the expression of INHA protein in testicle tissue was significantly decreased,while that in epididymis tail was significantly increased.This difference might affect the development of spermatogenic epithelium and help to adapt to high cold and low oxygen environment by regulating the secretion of follicle-stimulating hormone(FSH)and the process of spermatogenesis.In conclusion,in the high altitude low oxygen environment,the histomorphological changes of testicle,epididymal and deferens of Tibetan sheep may be the protective response to adapt to high altitude low oxygen environment;at the same time,Tibetan sheep at high altitude directly or indirectly affect spermatogenesis and maturation by regulating the expression of AR and INHA genes and proteins in reproductive organs.