Expression patterns of CXCR4, ITGB1, and FGFR3 in feline spermatogonial stem cells

Spermatogonial stem cells (SSCs) play a crucial role in preserving male fertility, and they are increasingly recognised as essential tools in conservation biology. However, the molecular identity of SSCs in domestic cats (Felis catus) remains insufficiently characterised. This study aimed to investigate the immunohistochemical expression patterns of three candidate markers Fibroblast Growth Factor Receptor 3 (FGFR3), Integrin β1 (ITGB1), and Chemokine Receptor Type 4 (CXCR4) in prepubertal and pubertal cat testes. Testicular tissues from five prepubertal and five pubertal cats were collected and classified based on histological evaluation of spermatogenic cells. Cryosections were obtained and analysed using immunofluorescence staining protocols combined with α-SMA and DAPI counterstaining. The expression patterns were evaluated on a fluorescence microscope, and quantitative fluorescence intensities were measured using ImageJ. Our results reveal that ITGB1 expression is robust and uniformly distributed throughout seminiferous tubules in both developmental stages, with no significant variation between groups (p > 0.05). In contrast, CXCR4 expression is significantly elevated in prepubertal testes compared to pubertal samples (p < 0.05), showing restricted localisation to basal compartments post-puberty. FGFR3 expression was primarily observed in gonocytes during the prepubertal period and localised to basal membranes and sperm tail regions during puberty, with no significant difference between pubertal and prepubertal groups (p > 0.05). These findings provide novel insights into the molecular characteristics of feline SSCs and offer a valuable foundation for the development of advanced reproductive technologies to preserve genetic diversity and support the conservation of endangered felid species.