PROBLEM: The dynamics of calpain and involvement of apoptosis in sperm formation disorder of the unaffected testis in rats with experimental testicular torsion were investigated.
METHODS OF STUDY: Using 6-week-old Wistar rats, an experimental unilateral testicular torsion model was prepared. The bilateral testes were excised 1, 3, 5, 7, 14, 35, and 70 days after the left testis was twisted, and the unaffected testes were subjected to immunohistological staining, sodium dodecyl sulfate polyacrilamide gel electrophoresis and Western blotting using anti-calpain antibodies. Apoptosis was detected by the TdT-mediated dUTP–biotin nick end-labeling (TUNEL) method.
RESULTS: By immunohistological staining, positive immunostaining by anti-pro μ-calpain antibody was observed in the spermatocyte nucleus, but not with anti-pro m-calpain antibody. The staining was increased until 7 days after testicular torsion, then decreased with progression of sperm formation disorder. By Western blotting, the intensity of staining with anti-pro μ-calpain antibody was increased until 7 days after torsion of the testis. Apoptosis expression in the unaffected testis was significantly inhibited by addition of a calpain inhibitor.
CONCLUSIONS: It was suggested that μ-calpain may be involved in apoptosis expression in sperm formation disorder of the unaffected testis in unilateral testicular torsion.