Testicular involution following optic enucleation. An ultrastructural and cytochemical study

Area of Science:

• Reproductive Biology
• Endocrinology
• Cell Biology

Background:

• The visual system influences reproductive function in many species.
• Optic enucleation, the removal of eyeballs, can disrupt hormonal regulation.
• Testicular involution is a significant decrease in testicular size and function.

Purpose of the Study:

• To investigate the effects of optic enucleation on the testes of adult male Syrian hamsters.
• To characterize the structural and cellular changes in the seminiferous tubules and Sertoli cells following optic enucleation.

Main Methods:

• Adult male Syrian hamsters underwent bilateral optic enucleation.
• Testes were collected six weeks post-surgery for histological and ultrastructural analysis.
• Lanthanum tracer studies were used to assess the integrity of the blood-testis barrier.

Main Results:

• Optic enucleation induced significant testicular involution, with a 39% reduction in seminiferous tubule diameter.
• Spermatids were completely absent, while Sertoli cells, spermatogonia, and primary spermatocytes persisted.
• Sertoli cells exhibited abundant lipid droplets, altered organelle content, and intact, impenetrable Sertoli-Sertoli junctions forming an intact blood-testis barrier.
• Abnormal protrusions from peritubular tissue and extensive leaf-like Sertoli cell processes occluding the lumen were observed.
• Degenerating germ cells were phagocytosed by Sertoli cells, with evidence of lysosomal activity and lipid droplet formation.

Conclusions:

• Optic enucleation causes severe disruption of spermatogenesis, specifically the loss of spermatids, in male Syrian hamsters.
• Despite significant testicular changes and germ cell loss, the blood-testis barrier remains structurally intact.
• Sertoli cell morphology is altered, with lipid accumulation and phagocytosis of degenerating germ cells, suggesting a role in clearing cellular debris.