Distinct effects of gonadectomy in mate and female mice on collagen fibrillogenesis in the skin

Background: Collagen biosynthesis and deposition is a complex, multistep process, which is tightly regulated to maintain proper tissue homeostasis. Sex steroid hormones have been implicated in regulating collagen synthesis; however the specific mechanisms regulating the process remain Largely unknown. Objective: To investigate the role of estrogens and androgens in the regulation of genes involved in collagen synthesis and fibrillogenesis using gonadectomized C57/B6 mice. Methods: Collagen content was assessed by hydroxyproline measurement and acetic acid extraction of collagen with or without the addition of pepsin. The mRNA levels of fibrillar collagens and enzymes involved in fibrillogenesis were determined by QPCR analysis. The protein expression of decorin, lumican and fibromodulin was confirmed by immunostaining. Results: We have shown that castration resulted in a markedly decreased skin thickness and collagen content without affecting collagen solubility. Furthermore, the mRNA levels of fibrillar collagen genes including types 1, 111, and V were decreased, suggesting that androgens positively regulate the rate of collagen gene transcription. Conversely, ovariectomy mainly affected collagen solubility. The absence of estrogens resulted in decreased expression levels of several of the small leucine-rich repeat proteins and proteoglycans (SLRPs) including decorin, fibromodulin and lumican.