Abstract

This study characterizes age-related morphometric and morphological changes in the epididymis of domestic cats (Felis silvestris catus) from puberty to adulthood (6 to 48 months), emphasizing its essential role in sperm maturation and storage-key processes for male fertility. A total of 42 epididymides were analyzed using histological staining (hematoxylin-eosin) and stereological quantification through the STEPanizer software. Morphometric analyses revealed an age-dependent increase in the diameter of the epididymal duct and epithelial height in the caput, whereas the cauda exhibited a progressive reduction in epithelial height, possibly reflecting adaptations in sperm storage capacity during sexual maturation. Morphological observations showed the presence of intraepithelial cysts in cats aged 24 to 48 months, along with the consistent detection of spermatozoa in all regions and age groups. Stereological findings indicated an increased volumetric density (%VV) of the ductal epithelium, particularly in the caput between 6 and 12 months of age, supporting the influence of androgenic activity on regional epididymal maturation. These changes suggest dynamic, age-related structural remodeling of the epididymal parenchyma, especially in epithelial and luminal components. While this cross-sectional study-conducted during the southern hemisphere spring-provides valuable insights into epididymal development, its design limits the establishment of causal relationships between age and histological changes. Future longitudinal studies examining hormonal modulation of epididymal maturation in domestic cats are encouraged. Overall, these findings contribute foundational knowledge of feline reproductive anatomy and underscore the importance of the epididymis as a hormonally responsive organ central to male fertility.