Morphometric profiling and EphB2/B4 and ephrin-B1 membrane protein expression analysis in vesicular, bulbourethral,...

Objectives: Male accessory sex glands are essential components of the reproductive system, providing secretions that support sperm function, fertility, and androgen-dependent reproductive processes. Despite the widespread use of mice as experimental models, comprehensive biometrical, histomorphometrical, and molecular characterization of their accessory sex glands remains limited. The present study investigated the vesicular, bulbourethral, and preputial glands of adult male mice with particular emphasis on biometric parameters, histological organization, and the expression of EphB2, EphB4, and ephrin-B1 membrane proteins. Materials and Methods: Ten-week-old male ICR mice (n = 6) were used for morphometric profiling, RT-PCR, and immunofluorescence analyses. Results: The vesicular glands showed highly folded mucosa lined by pseudostratified columnar epithelial cells and enclosed by well-developed smooth muscle layers. Bulbourethral glands were multilobular, composed of arborized acini lined by tall columnar epithelial cells, whereas preputial glands were modified sebaceous glands characterized by lobulated sebaceous acini with prominent basal cells. RT-PCR analysis revealed the presence of EphB4 and ephrin-B1 transcripts in all three glands, while EphB2 expression was detected only in the vesicular and bulbourethral glands. Immunofluorescence staining demonstrated that EphB4 and ephrin-B1 were predominantly localized in basal cells of vesicular and preputial glands and in secretory epithelial cells in the bulbourethral gland, with weaker expression in principal cells in the vesicular gland. Faint expression of EphB2, EphB4, and ephrin-B1 was observed in α-SMA-positive smooth muscle cells of vesicular and bulbourethral glands. Conclusions: The findings provide the first integrated biometric and histomorphometric data and demonstrate distinct expression profiles of EphB2/B4 and ephrin-B1 membrane proteins in mouse accessory sex glands, suggesting their involvement in glandular structure and functional regulation.