Suppression of NADPH oxidase- and mitochondrion-derived superoxide by Notoginsenoside R1 protects against cerebral ischemia-reperfusion injury through estrogen receptor-dependent activation of Akt/Nrf2 pathways.
Notoginsenoside R1 (NGR1) is a novel phytoestrogen that is isolated from Panax notoginseng. We have recently found that NGR1 showed neuroprotection in vitro against oxidative stress through estrogen receptor (ER)-dependent activation of Akt/Nrf2 pathways. However, whether NGR1 has neuroprotective effect against cerebral ischemia-reperfusion (I/R) injury in vivo is unknown. In this study, we used in vivo and in vitro models of cerebral I/R injury that demonstrate middle cerebral artery occlusion and reperfusion in rats, as well as oxygen-glucose deprivation followed by reoxygenation (OGD/R) in primary cortical neurons. These models were used to evaluate NGR1 neuroprotection. Three-day pretreatment with NGR1 (20 mg/kg; i.p.) significantly improved neurologic outcomes and reduced cerebral infarct volume. Pretreatment of primary cortical neurons with NGR1 (25 μM) for 24 h prevented apoptosis and oxidative stress induced by OGD/R. NGR1 inhibited apoptosis by inhibiting mitochondrial membrane potential disruption, caspase-3 activation, and DNA fragmentation. NGR1 prevented oxidative stress by suppressing NADPH oxidase- and mitochondrion-derived superoxide and inhibiting production of malondialdehyde, protein carbonyl, and 8-hydroxydeoxyguanosine in vivo and in vitro. NGR1 induced ER-dependent activation of Akt/Nrf2 pathways by increasing ERα, ERβ, phospho-Akt, phospho-GSK3β, nuclear Nrf2, and HO-1 expression in vivo and in vitro. Pretreatment with ICI-182780, LY294002, or Snpp abolished NGR1-mediated neuroprotection against oxidative stress and apoptosis in vitro. In conclusion, NGR1 showed neuroprotection against cerebral I/R injury in vivo and in vitro. The mechanism of NGR1 neuroprotection involves inhibition of NADPH oxidase activity and mitochondrial dysfunction via ER-dependent activation of Akt/Nrf2 pathways.
Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing , P. R. China.
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D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D036145:Ginsenosides / Q000737:chemistry / Q000494:pharmacology*; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control; D008297:Male; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D015394:Molecular Structure; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000378:metabolism*; D018696:Neuroprotective Agents / Q000737:chemistry / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D013481:Superoxides / Q000037:antagonists & inhibitors* / Q000378:metabolism
D036145:Ginsenosides; D051267:NF-E2-Related Factor 2; D018696:Neuroprotective Agents; D011960:Receptors, Estrogen; D013481:Superoxides; D019255:NADPH Oxidases; D051057:Proto-Oncogene Proteins c-akt; C072936:notoginsenoside R1
Cerebral ischemia–reperfusion injury; NADPH oxidase; apoptosis; oxidative stress; superoxide