title: Nitric oxide promotes germ cell necrosis in the delayed phase after experimental testicular torsion of rat.
abstract: The purpose of this study is to determine whether inducible nitric oxide synthase (iNOS) is involved in the pathogenesis of testicular ischemia-reperfusion (I/R) injury in association with germ cell death, through either necrosis or apoptosis. Western blot analysis showed that iNOS expression was markedly increased 1 h after ischemia, and was accompanied by a huge nitric oxide (NO) production, as measured by the Griess method, with a peak at 48 h of reperfusion. Immunohistochemistry showed that iNOS was expressed predominantly in the macrophage-like cells infiltrated in the interstitial tissues of the testis. Intraperitoneal injection of aminoguanidine (AMG) (400 mg/day), the inhibitor of iNOS, reduced NO production by 57.7% at 96 h of reperfusion. Calpain activation and proteolysis of alpha-fodrin induced by I/R were inhibited by AMG. Germ cell apoptosis was demonstrated by in situ TUNEL and DNA fragmentation on agarose gel electrophoresis. Germ cell apoptosis was maximally induced at 24 h of reperfusion, and was not inhibited by AMG. NO produced by iNOS in the delayed phase of reperfusion promoted alpha-fodrin proteolysis, which is closely associated with necrosis. Inducible NOS inhibition combined with calpain inhibition may improve impaired spermatogenesis after testicular torsion.
authors.affiliation: Department of Urology, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan. legal@po.cc.yamaguchi-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Shiraishi
authors.forename: K
authors.initials: K
authors.lastname: Naito
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002154:Calpain / Q000378:metabolism; D053938:DNA Fragmentation; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D015151:Immunoblotting; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D007700:Kinetics; D008297:Male; D009336:Necrosis; D009569:Nitric Oxide / Q000032:analysis / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D051381:Rats; D017208:Rats, Wistar; D013086:Spermatic Cord Torsion / Q000473:pathology*; D013091:Spermatogenesis / Q000187:drug effects; D013094:Spermatozoa / Q000473:pathology*; D013737:Testis / Q000737:chemistry
chemical_list: D004791:Enzyme Inhibitors; D006146:Guanidines; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D002154:Calpain; C004479:pimagedine