ABSTRACT
Oxidative stress(OS)is a major reason for body damage. Studies have shown that a variety of factors, such as ischemia and hypoxia, excessive light and hyperglycemia can cause the increase of reactive oxygen species and free radicals in the retina, thus inducing OS, damaging retina and affecting the normal visual function. Kelch-like ECH-associated protein 1(KEAP1)and nuclear factor erythroid 2 related factor 2(NRF2), which together constitute the main antioxidant stress signaling pathway in the body, play an antioxidant role by regulating retinal energy metabolism and cell proliferation, apoptosis and autophagy through various ways, so as to reduce retinal damage caused by OS. In this paper, the role and mechanism of the KEAP1-NRF2 signaling pathway regulation of OS in the retinal are briefly reviewed, aiming to provide ideas for subsequent research.
ABSTRACT
AIM:To investigate the effects of ginsenoside RH 2(GS-RH2 )on neovascularization of rats with middle cerebral artery occlusion(MCAO)and its potential mechanisms.METHODS:SPF Sprague-Dawley rats were ran-domly divided into sham operation(sham)group,MCAO model(MCAO)group and GS-RH2 group,with 18 rats in each group.After surgery,the general condition and neurological function score of the rats were assessed.At the 1st day,3rd day and 7th day after intervention,the microvessel density(MVD),the content of malondialdehyde(MDA)and the activ-ity of superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)were examined.The protein expression of kelch-like ECH-associated protein 1(Keap1),nuclear factor E2-related factor 2(Nrf2)and heme oxygenase-1(HO-1)was de-termined by Western blot.RESULTS:Compared with sham group ,the rats in MCAO group showed significant neurobe-havioral obstacles and ischemic brain infarction with higher neurological function score ,while treatment with GS-RH2 sig-nificantly improved behavioral impairment and reduced the infarction volume with lower neurological function score.The MVD score in GS-RH2 group was increased as the animal survival time prolonged ,while the MVD score in MCAO group was decreased.After intervention for 7 d,the MVD score in GS-RH2 group was significantly higher than that in MCAO group(P<0.05).Compared with sham group,the content of MDA was increased and the activities of SOD and GSH-Px were decreased in MCAO group at each time point.After intervention for 7 d,the MDA content was decreased and the SOD and GSH-Px activities were increased in GS-RH2 group compared with MCAO group.After intervention for 7 d,the protein expression of Nrf2 and HO-1 was increased,while the protein expression of Keap1 was decreased in GS-RH2 group com-pared with MCAO group(P<0.05).CONCLUSION:Ginsenoside RH2 promotes neovascularization of MCAO model rats.The mechanism may be related to the activation of Keap 1/Nrf2 signaling pathway ,promotion of the antioxidant enzyme activity and inhibition of oxidative stress.