title: Effects and Mechanism of Action of Inducible Nitric Oxide Synthase on Apoptosis in a Rat Model of Cerebral Ischemia-Reperfusion Injury.
abstract: Inducible nitric oxide synthase (iNOS) is a key enzyme in regulating nitric oxide (NO) synthesis under stress, and NO has varying ability to regulate apoptosis. The aim of this study was to investigate the effects and possible mechanism of action of iNOS on neuronal apoptosis in a rat model of cerebral focal ischemia and reperfusion injury in rats treated with S-methylisothiourea sulfate (SMT), a high-selective inhibitor of iNOS. Seventy-two male Sprague-Dawley (SD) rats were randomly divided into three groups: the sham, middle cerebral artery occlusion (MCAO) + vehicle, and MCAO + SMT groups. Neurobehavioral deficits, infarct zone size, and cortical neuron morphology were evaluated through the modified Garcia scores, 2,3,5-triphenyltetrazolium chloride (TTC), and Nissl staining, respectively. Brain tissues and serum samples were collected at 72 hr post-reperfusion for immunohistochemical analysis, Western blotting, Terminal deoxynucleotidyl transferase-mediated dUTP-biotin Nick End Labeling assay (TUNEL) staining, and enzyme assays. The study found that inhibition of iNOS significantly attenuated the severity of the pathological changes observed as a result of ischemia-reperfusion injury: SMT reduced NO content as well as total nitric oxide synthase (tNOS) and iNOS activities in both ischemic cerebral hemisphere and serum, improved neurobehavioral scores, reduced mortality, reduced the infarct volume ratio, attenuated morphological changes in cortical neurons, decreased the rate of apoptosis (TUNEL and caspase-3-positive), and increased phospho (p)-AKT expression in ischemic penumbra. These results suggested that inhibition of iNOS might reduce the severity of ischemia-reperfusion injury by inhibiting neuronal apoptosis via maintaining p-AKT activity.
authors.affiliation: Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
authors.forename: Li
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Department of Neurology, the Center Hospital of China Natural Petroleum Corporation, Lang Fang, 065000, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Ding
authors.affiliation: Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
authors.forename: Jianwei
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
authors.forename: Changman
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
authors.forename: Weiguang
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects; D015153:Blotting, Western; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020287:In Situ Nick-End Labeling; D020244:Infarction, Middle Cerebral Artery / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D007550:Isothiuronium / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*
chemical_list: D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D007550:Isothiuronium; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D051057:Proto-Oncogene Proteins c-akt; C027744:S-methylisothiopseudouronium
keywords: apoptosis; cerebral ischemia and reperfusion injury; inducible nitric oxide synthase; p-AKT