The Mechanism Of The Protective Effect Of Resveratrol In Neural Degeneration Of Diabetic Retinopathy

Background: Recent research reveals that the oxidative stress induced neural degeneration is a fundamental pathological change in the progression of diabetic retinopathy.Resveratrol is a polyphenolic compound with multiple pharmacological functions and exhibits protective phenomenon in a lot of neural degenerative diseases owing to its anti-oxidation,anti-ageing,anti-inflammation effects.However,the effect of resveratrol on neural degeneration of diabetic retinopathy is not fully elucidated,and our research is aimed at determining the protective features of resveratrol in the field.Methods: The diabetic mouse model is constructed by STZ intraperitoneally administration,and the mouse blood glucose were monitored every week.The apoptosis and oxidative stress level were evaluated by TUNEL staining,DHE staining,8-OHd G staining in control,diabetic,and resveratrol treated diabetic mouse retina.Western blot is used for detecting p-H2 A.X,Sirt1,Nrf-2 and PARP1.Similarly,the mitochondrial membrane potential,as well as ROS,SOD and NAD+/NADH content,were measured in the neuro-2a cells under different glucose and resveratrol stimulation in cells.Western blot was used to test the protein expression of Sirt1,Nrf-2,HO-1,PARP1 in cells under different stimulation,while the transcriptional level of sirt1,nrf-2,ho-1,nqo-1,cat,parp1 was determined by RT-PCR.Simultaneously,the ROS and SOD level was retested after the application of Ex527,an inhibitor for Sirt1.Moreover,Sirt1,Nrf-2,HO-1,P-H2 A.X were also determined by western blot.Results: Compared to the diabetic group,the retinal ganglion cells are stained with less TUNEL,DHE and 8-OHd G in mice retina in the diabetic resveratrol treated group,accompanied by an elevation of Sirt1 and Nrf-2 and a decrease of PARP1.Under high glucose stimulation,resveratrol protects Neuro-2a cells from apoptosis by upregulating the mitochondrial membrane potential,and alleviated ROS,raised SOD and total NAD content in vitro model.The high glucose resveratrol treated group also elevated the protein expression of Sirt1,Nrf-2,HO-1,as well as the transcription of sirt1,nrf-2,ho-1,nqo-1,cat.The NADH content varied between the 1μM and the 10μM resveratrol treated group.Under high glucose,PARP1 expression decreased in 0.1μM and 1μM resveratrol treated group,but not in 5μM and 10μM group,which reduced NAMPT expression.Sirt1 inhibition abrogated the anti-oxidation effect of resveratrol by raising ROS and decreasing SOD,accompanied by a decrease in Nrf-2,HO-1 and an increase in P-H2 A.X.Conclusion: Resveratrol could protect the retinal ganglion cells from apoptosis via reducing the oxidative stress through the activation of Sirt1/Nrf-2/HO-1 pathway,and by decreasing the level of PARP1 to preserve NAD.