Testicular sperm maturation is critical for establishing male fertility. Spermatozoa undergo remodeling of sperm proteins and changes in lipid and ribonucleic acid composition during transport in the epididymal ducts, which play an important role in sperm maturation. The anatomy, epithelial cell types, physiological functions, and epigenetic inheritance of the epididymis are explored, and recent findings in epididymal research are analyzed. Suggesting possible directions for future research on the epididymis. Using the keywords “epididymis”, “sperm”, and “sperm maturation”, a search of the epididymis was performed through databases and official websites of journals related to reproduction. The epididymis was searched in databases and on the official websites of journals related to reproduction. This review introduces the characteristics of the epididymis, as well as the biological functions of cell types such as principal cells, clear cells, and basal cells, providing a detailed description of the overall physiological functions of the epididymis. It highlights current research hotspots in the field of epididymis, including single-cell analysis, epigenetics, and extracellular vesicles, aiming to offer a comprehensive understanding for beginners. The review emphasizes the importance of the epididymis, its impact on sperm maturation and subsequent embryo development, and how it advances research on epididymal diseases while providing new directions for the study and treatment strategies of infertility.

Epididymitis or epididymo-orchitis is a common urological condition in males characterized by scrotal pain, swelling, and potential urinary symptoms. Although antibiotics can eliminate the causative pathogens, persistent inflammation may compromise spermatogenesis and steroidogenesis. The testis, an immune-privileged organ, possesses a specialized immune microenvironment that shields germ cells (GCs) from autoimmune attacks and orchestrates immune defenses against pathogens. This review focuses on the complex interplay between immune cells, including macrophages, dendritic cells (DCs), mast cells (MCs), and T cell subsets, in the testis. The roles of these immune cells in infection-induced orchitis were deliberated upon, emphasizing their involvement in inflammation and immune tolerance. Furthermore, the implications of testicular fibrosis and its effect on male infertility are discussed, emphasizing the role of MCs in tissue remodeling. The objective of this review is to expand comprehension of male reproductive health and foster the identification of potential therapeutic targets for epididymo-orchitis.