Distinct testicular somatic cell profiles in cattle-yak with spermatogenic arrest compared to yak

The spermatogonial stem cell microenvironment constitutes a sophisticated system formed by various testicular somatic cells, which collectively maintain normal spermatogenesis through multiple mechanisms, including paracrine factor secretion, direct intercellular contact, and structural support provided by the extracellular matrix. This investigation focused on the isolation and identification of Leydig, Sertoli, and peritubular myoid cells from cattle-yak and yak testes. The primary goal was to reveal potential differences in the properties of these cells by comparing their in situ characteristics within the testis with those observed in vitro. The results revealed distinct differences in the proliferative activity of three types of testicular somatic cells in cattle-yaks compared to yaks. The expression of genes related to testosterone synthesis in the Leydig cells of cattle-yak was up-regulated, and the activity of testosterone secretion was elevated. The expression of genes related to the blood-testis barrier in Sertoli cells of cattle-yak was down-regulated, and the secretion activity of inhibin B was also enhanced. The expression of protein factors related to the proliferation and differentiation of undifferentiated spermatogonia and spermatogenesis in peritubular myoid cells of cattle-yak was altered. The results suggested that the altered proliferation and functional activity of testicular somatic cells may be associated with impaired spermatogenesis, potentially contributing to the arrest of spermatogenesis in the cattle-yak. This work provides new insights for addressing the issue of male sterility in cattle-yak.