Cytokines and adipokines in the regulation of spermatogenesis and semen quality

Male reproductive tract inflammation/infection possibly has a direct association with the occurrence of male infertility. Semen quality has been reported to be markedly reduced in conditions of male reproductive tract inflammation owing to functional or anatomical alterations in the reproductive tract such as accessory glands dysfunctions, obstructions in sperm transport, or spermatogenic disruptions by the inflammatory microenvironment. The severity of the inflammatory process and the level of impairment in male reproductive functions are associated with the roles played by individual inflammatory mediators, prominently the cytokines, adipokines and the reactive oxygen species (ROS). The mutual interactions of these biologically active substances originating mostly from the activated seminal leukocytes adversely affect testicular functions and deteriorate semen quality. However, several aspects regarding the association of inflammation, pro-inflammatory mediators and male infertility need to be clarified. Thus, the current review aims to present the roles of cytokines and adipokines in the context of understanding the mechanisms of inflammation-induced alterations in semen quality.