Monocytic orchitis and aspermatogenesis in normal and vasectomized rhesus macaques (Macaca mulatta)

Area of Science:

• Reproductive immunology
• Urologic pathology
• Primate research

Background:

• Vasectomy is a common contraceptive procedure.
• Potential immunologic consequences of vasectomy are not fully understood.
• Previous studies suggest vasectomy may induce immune responses against sperm.

Purpose of the Study:

• To compare immunopathologic findings in testes and kidneys of vasectomized and control monkeys.
• To investigate the incidence and characteristics of immune responses following vasectomy.
• To explore the potential immunologic basis of testicular pathology after vasectomy.

Main Methods:

• Comparative analysis of testicular and kidney tissues from 25 vasectomized and 13 control monkeys.
• Detection of antisperm antibodies in serum samples.
• Immunofluorescence studies to identify immune deposits (IgA, IgG, C3, IgM) in reproductive tissues.
• Histopathological examination for orchitis, aspermatogenesis, epididymitis, and granuloma.

Main Results:

• Antisperm antibodies were found in 60% of vasectomized monkeys versus 0% of controls.
• Orchitis or aspermatogenesis occurred in 92% of vasectomized animals compared to 23% of controls.
• Immune deposits in the excurrent duct system increased significantly in vasectomized animals (91% vs 45%) and included C3 in the glomeruli (29% vs 0%).
• Epididymitis and epididymal granuloma were exclusive to vasectomized animals (52%).

Conclusions:

• Vasectomy in non-human primates is associated with increased antisperm antibodies and immune complex deposition in the testes and kidneys.
• Pathological changes, including orchitis and aspermatogenesis, are more prevalent after vasectomy and resemble allergic orchitis.
• The findings suggest an immunologic basis for testicular pathology following vasectomy, though further investigation is warranted to establish causality.