S-100 proteins expression in the testis of dromedary camel during breeding and non-breeding seasons: molecular and immunohistochemical studies

The current study was undertaken to investigate the relationship between the expression of S-100 gene in testicular tissue and reproductive activity in dromedaries. Testicular tissue specimens were taken from 5 sexually immature and 5 adult camels per season throughout the year. Specimens were examined molecularly and histologically. Histological findings showed that spermatogenic activity was totally absent in sections from immature camels throughout the year. However, in adults the activity was the highest in winter, moderate during spring and autumn and almost absent in summer. The seminiferous epithelium and interstitial cells displayed degenerative changes that were more evident in summer and absent or less evident in winter. Sections from immature camels showed that interstitial cells (ISCs) exhibit a moderate (winter, spring and autumn) and weak (summer) S-100-immunoreactivity (S-100-IR). In adults a strong, moderate and weak S-100-IR was found in sertoli cells in winter, during spring and autumn, and in summer, respectively. Additionally, ISCs showed moderate, weak and negative S-100-IR in winter, during spring and autumn, and in summer, respectively. The expression of S-100 mRNA was significantly higher in adult camels in winter compared to adults within other seasons, and to immature ones in the same season. Taken together the seasonal variation in the gene expression in respect to histological profile and sexual activity, suggested that S-100 proteins play a significant role in regulation of both exocrine and endocrine testicular functions in camel.