Identification and function analysis of macrophages subsets in chronically inflamed human epididymis

Chronic epididymitis is amongst the leading causes of male infertility. The main clinical manifestations of chronic epididymitis included oligozoospermia and asthenospermia. Our previous studies showed that over-expression of dendritic cells (DCs) and secreting cytokines were found in chronically inflamed human epididymis. They were thought to play a key role in the immune response of chronic epididymitis. The object of this study was to investigate the expression and characteristic of macrophage subsets in chronic epididymitis and its controls. Our study demonstrated that both inducible nitric oxide synthase (iNOS) +CD68+ M1 and CD163+CD206+ M2 macrophages were significantly increased in the chronic inflammation of human epididymis compared with its controls. Moreover, CD68+iNOS+ M1 and CD163+CD206+ M2 macrophages were observed to capture spermatozoa in the lumen of cauda epididymidis. The CD68+ M1 macrophages in chronically epididymitis expressed cytokines IL-6 and IL-23p19; meanwhile, CD163+ M2 macrophages expressed transforming growth factor-β (TGF-β), vascular endothelial growth factor (VEGF) and IL-23p19. In addition, Th1 (CD3+IFN-γ+) cells were predominantly distributed in the chronically epididymitis. Taken together, our results indicate that epididymal macrophages may play an important role in the development of chronic epididymitis and induce oligozoospermia and asthenospermia of male infertility patients.