| Objective: To successfully establish retinal ischemia-reperfusion(IR)injury model in mice.And to observe the changes of retinal cells,retinal function,and SIRT1 expression after retinal IR injury.Methods: Retinal IR injury model was induced in C57BL/6J mice.The anterior chamber of the left eye was cannulated only,while the intraocular pressure(IOP)of the right eye was increased by adding saline for 1 hour.Mice were sacrificed 3,7,and 14 days after retinal ischemia.The IOP before,during,and after retinal ischemia was recorded.Retinal ganglion cells(RGCs)and microglia were stained with Brn3 a and Iba1 respectively in retinal sections and flat-mounts.Retinal function was evaluated by flash electroretinogram(F-ERG).Expression of SIRT1 was detected by western blot.Results:(1)Normal IOP was about 7.6 ± 1.1 mm Hg.The IOP reached above 60 mm Hg during retinal ischemia,quickly decreased after removing the needle,and maintained within normal level after that.(2)The loss and the derangement distribution of RGCs were observed over time after IR injury(P<0.05).(3)The number of microglia increased over time after IR injury.In IR3 and IR7 groups,the branched microglia were activated to the ameboid microglia.While in IR14 group,the cell bodies were small,and the processes were short.(4)The amplitudes of a-wave and b-wave decreased sharply after IR injury(P<0.01).(5)The SIRT1 expression decreased over time after IR injury,which was most significant in IR7 and IR14 groups(P<0.05).Conclusion: Retinal IR injury is a well-established experimental model for retinal neurodegenerative diseases such as glaucoma.RGCs loss,microglia activation,and retinal dysfunction are the most important pathological features,in which the reduction of SIRT1 expression might be involved.Objective: To successfully establish retinal ischemia-reperfusion(IR)injury model after intravitreal injection of resveratrol(RSV)and sirtinol in mice.To observe the effects of RSV and sirtinol on SIRT1 expression,retinal ganglion cells(RGCs),and retinal function after IR injury.And to explore whether the neuroprotective effects of RSV are mediated through SIRT1-related pathways.Methods: C57BL/6J mice were randomly divided and treated as follow: IR7 group: Retinal IR injury was induced in the right eye,and mice were sacrificed 7 days after retinal ischemia.Intravitreal injection+IR7 groups: PBS,10?M,50?M,100?M RSV,and 100?M sirtinol were injected or co-injected intravitreally 1 day before retinal IR injury in the right eye,and mice were sacrificed 7 days after retinal ischemia.The IOP before,during,and after retinal ischemia was recorded.Expression of SIRT1 was detected by western blot.RGCs were stained with Brn3 a in retinal sections and flatmounts.Retinal function was evaluated by flash electroretinogram(F-ERG).Results:(1)The IOP kept within normal level before and after intravitreal injection,reached above 60 mm Hg during retinal ischemia,quickly decreased after removing the needle,and maintained within normal level after that.(2)RSV enhanced SIRT1 expression in a dose-dependent manner(P<0.05),and this up-regulation was blocked by the co-injection of sirtinol(P<0.05).(3)Compared with IR7 group,RSV increased RGCs survival rate in a dose-dependent manner,especially at the concentration of 100?M(P<0.05).And compared with 100RSV+IR7 group,RGCs survival rate in 100RSV+100Sirtinol+IR7 group was obviously lower(P<0.05).(4)Compared with IR7 group,100?M RSV significantly increased the amplitude of b-wave(P<0.01).Conclusion: SIRT1 expression can be regulated by the intravitreal injection of the activator RSV and the inhibitor sirtinol.RSV attenuated RGCs loss in a dose-dependent manner,and improved retinal function.All changes above can be blocked by sirtinol,indicating that the neuroprotection of RSV is mediated through SIRT1-related pathways.Objective: To observe the effects of intravitreal injection of resveratrol(RSV)and sirtinol on apoptotic morphology and biochemistry after retinal ischemia-reperfusion(IR)injury in mice.And to explore whether SIRT1 up-regulation by RSV confers neuroprotection in retinal IR injury through the inhibition of apoptotic pathways.Methods: C57BL/6J mice were randomly divided and treated as follow: Control and IR7 groups: The anterior chamber of the left eye was cannulated only,while the intraocular pressure(IOP)of the right eye was increased by adding saline for 1 hour,and mice were sacrificed 7 days after retinal ischemia.Intravitreal injection+IR7 groups: PBS,10?M,50?M,100?M RSV,and 100?M sirtinol were injected or co-injected intravitreally 1 day before retinal IR injury in the right eye,and mice were sacrificed 7 days after retinal ischemia.Expressions of phospho-Akt(p-Akt),Akt,Bax,and Bcl-2 were detected by western blot.Retinal sections were stained with cleaved caspase-3 and TUNEL.Results:(1)SIRT1 up-regulation by RSV increased p-Akt expression(P<0.05),decreased Bax expression(P<0.05),and these effects were blocked by the co-injection of sirtinol(P<0.05).There were no significant changes in Akt and Bcl-2 expressions.(2)Compared with control group,abundant cleaved caspase-3-positive and TUNELpositive cells were observed after retinal IR injury.And compared with IR7 group,RSV effectively reduced cleaved caspase-3-positive and TUNEL-positive cells,and these effects were blocked by the co-injection of sirtinol.Conclusion: SIRT1 up-regulation by RSV confers neuroprotection in retinal IR injury through the inhibition of apoptotic pathways.Intravitreal injection of RSV enhanced SIRT1 expression,activated Akt pathway,decreased Bax level,inhibited cleaved caspase-3 expression,and finally suppressed the mitochondrial apoptotic pathway. |
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