title: Inhibition of nNOS reduces ischemic cell death through down-regulating calpain and caspase-3 after experimental stroke.
abstract: In vitro nitric oxide (NO) regulates calpain and caspase-3 activation, and in vivo neuronal nitric oxide synthase (nNOS), calpain and caspase-3 participate in the ischemic brain injury. Our objective was to investigate whether nNOS was involved in the ischemic brain injury through activating calpain and caspase-3 during experimental stroke. Rats received 1-h ischemia by intraluminant filament, and then reperfused for 23h (R 23h). nNOS inhibitor 7-nitroindozale (7-NI, 50mg/kg) was administrated intraperitoneally 5min before ischemia. Our data showed that treatment with 7-NI markedly reduced neurological deficits, the brain swelling, and the infarct volume at R 23h. Enzyme studies revealed significant suppression of the activities of m-calpain and caspase-3 in penumbra and core, and the activities of mu-calpain in penumbra, but not in core, in 7-NI-treated rats versus vehicle-treated rats. Western blot analysis demonstrated that 7-NI markedly increased the levels of MAP-2 and spectrin in penumbra and core compared with vehicle-treated rats. Histopathological studies displayed that 7-NI significantly reduced the necrotic cell death in penumbra and core, and apoptotic cell death in penumbra, but not in core. These data demonstrate the involvement of NO produced by nNOS in the ischemic neuronal injury through affecting the activation of calpain and caspase-3 in penumbra and core after experimental stroke, which provides a new perspective on possible mechanisms of action of nNOS inhibition in cerebral ischemia.
authors.affiliation: Department of Neurochemistry, Beijing Neurosurgical Institute, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.forename: Yumei
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yi
authors.initials: Y
authors.lastname: Gu
authors.forename: Chao
authors.initials: C
authors.lastname: Xu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001929:Brain Edema / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D002154:Calpain / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism*; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020925:Hypoxia-Ischemia, Brain / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology; D007191:Indazoles / Q000494:pharmacology; D008297:Male; D008869:Microtubule-Associated Proteins / Q000187:drug effects / Q000378:metabolism; D009336:Necrosis / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D009410:Nerve Degeneration / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D018696:Neuroprotective Agents / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013049:Spectrin / Q000187:drug effects / Q000378:metabolism; D020521:Stroke / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology
chemical_list: D004791:Enzyme Inhibitors; D007191:Indazoles; D008869:Microtubule-Associated Proteins; C079240:Mtap2 protein, mouse; D018696:Neuroprotective Agents; D013049:Spectrin; D009569:Nitric Oxide; D052248:Nitric Oxide Synthase Type I; D002154:Calpain; D053148:Caspase 3; C080122:7-nitroindazole