iNOS Expressions in Torsed and Contralateral Testes in the Rats

Seo, Il Young; Park, Kyung Won; Han, Weon Cheol; Rim, Joung Sik

Abstract

PURPOSE: Some authors noted unilateral testicular torsion often leading to a damage in the contralateral testis. But it is not known whether this is the result of an intrinsic abnormality in the remaining testis or testicular injury associated with the ischemic event. Recently some authors noted an increase in germ cell apoptosis in the contralateral testis and suggested the involvement of nitric oxide (NO) in the apoptosis of germ cells. We aimed at the NO involvement in testicular torsion in this study, in which we measured inducible nitric oxide synthase (iNOS) expressions and found pathological changes in the torsed and detorsed testes of the rats.
MATERIALS AND METHODS
Adult, male, Sprague-Dawley rats were divided into two groups: I) unilateral left testicular torsion persisting for 1, 4, 8 hours. II) torsion for 4 or 8 hours followed by detorsion. Testes were fixed in scrotal wall with a suture. Testes were fixed in formalin solution and prepared in paraffin blocks and slide mounted. All histologic examinations were done by a single observer. The expression of iNOS gene in the testis was determined by reverse transcriptase-polymerase chain reaction and relative iNOS mRNA levels were assessed with normalization to beta-actin mRNA levels.
RESULTS
Histologically, the degeneration and inflammation were found in 4 hours after torsion and the necrosis was found in 8 hours after torsion. In contralateral testis, normal findings were noted in 4 hours and 8 hours after torsion. iNOS gene expression was found in the normal control testis. In the torsed testis, iNOS gene expression significantly increased in 1 hour after torsion, then decreased to the control level. In contralateral testis, iNOS gene expression was also increased in 1 hour to 8 hours after torsion. After detorsion, iNOS gene expression significantly decreased in detorsed testis, but constantly increased in contralateral testis.
CONCLUSIONS
In rats, iNOS gene expression and histological changes were observed in torsed and detorsed testes. These results support the hypothesis that NO by iNOS protein may play a role in contralateral testicular damage, such as ischemic-reperfusion injury.