Changes in the testicular capsule and peritubular boundary tissue in pre-pubertal, pubertal and adult Japanese quails (Coturnix Coturnix Japonica)

Abstract

The aim of this study was to investigate age-related changes in the morphology of the peritubular boundary tissue and the testicular capsule of pre-pubertal, pubertal, and adult Japanese quails. The peritubular boundary tissue and testicular capsule are involved in the propulsion of spermatozoa from the seminiferous tubules into the excurrent duct system. In addition, the peritubular boundary tissue is thought to contribute to the formation of the blood-testis barrier. The use of transmission electron microscopy, as well as the immunolocalization of key cytoskeletal proteins revealed that the testicular capsule in the Japanese quail was composed predominantly of smooth muscle cells with relatively few fibroblasts. Furthermore, the use of histochemistry demonstrated the presence of collagen and reticular fibres in the testicular capsule, with a few elastic fibres present only in adult quails. In the current study, the morphology of the peritubular boundary tissue varied with testicular maturation. The results showed a reduction in the number of peritubular cell layers surrounding the seminiferous tubules as the birds matured. In addition, immunohistochemistry revealed age-related changes in the localization of cytoskeletal and basement membrane proteins.