Seasonal studies on morphology and immunohistochemical localisation of s-100 and alpha smooth muscle actin proteins in poll glands of dromedary camel

The two poll glands rest subcutaneously behind the ear of the dromedary camel (Camelus dromedarius). Although they secrete a watery yellowish secretion with offensive odour during breeding seasons, their function is still largely unspecified. This study on camel poll glands morphology and immunoreactivity of S-100 and alpha smooth muscle actin (α-SMA) proteins during breeding and non-breeding seasons might shed some light on their function. During breeding season the gland was larger in size and darker in colour and its secretion increased compared to non-breeding season. No significant change was observed in the alveolar luminal diameter during seasonal reproductive cycle (P>0.05). However, alveolar diameter and epithelial height was significantly (P<0.05) increased during breeding season together with significantly increased inter-alveolar tissue thickness during non-breeding season. While S-100 reacted positively in the alveolar epithelium and inter-alveolar tissue, α-SMA reaction was negative in the alveolar epithelium and positive in the alveolar myoepithelial cells, smooth muscles and blood vessels. S-100 and α-SMA positive immunoreactivity increased during breeding season compared to non-breeding season. These results suggest that the poll gland secretory activity is correlated with male camel seasonal sexual activity. Moreover, S-100 and α-SMA are suggested to regulate cellular and muscular functions in the poll glands.