Abstract
The effects of androgens on human skin mainly include the regulation of growth and differentiation of hair follicles and sebaceous glands. Androgens may have some physiological roles in sheep skin that are similar to those of humans, but further confirmation is needed. Therefore, Hetian sheep were chosen in this study as an animal model to explore the effects of testosterone on skin structure and factors related to androgen conversion and binding in Hetian sheep. The sheep were treated with different concentrations of testosterone for 42 days. Skin tissue sections were prepared and then subjected to hematoxylin-eosin, Sacpic, Masson's trichrome, and Oil Red O staining to observe changes in skin morphology. Changes in the content of blood-related factors were also detected using ELISA kits. The skin tissue distribution of androgen receptor was explored by immunohistochemistry and immunofluorescence assays. The results showed that testosterone significantly increases the sebaceous gland area and stimulates the formation of new sebaceous glands. Further exploration revealed that testosterone promotes the proliferation of sebaceous gland juvenile cells. However, testosterone was found to have no significant effect on hair follicle density and hair follicle structure. Testosterone increased dihydrotestosterone levels but decreased 5α-reductase 1 and 5α-reductase 2 levels. The androgen receptors were distributed in the hair follicles, sebaceous glands, and some major skin appendages of Hetian sheep. This study suggests that androgens can be effective in regulating sebum production in sheep. This study will help advance research efforts to further explore the molecular and cellular mechanisms by which androgens modify sheep follicles and sebaceous glands.