| Objective:Vascular dementia(VD)refers to a cognitive impairment caused by vascular factors,with dysfunctions such as learning,memory,and understanding as the main clinical symptoms.The specific pathogenesis is not fully understood.This experiment plans to use bilateral common carotid artery occlusion(BCCAO)to establish a VD rat model of cognitive dysfunction caused by chronic cerebral ischemia,and then give resveratrol(RSV)drug intervention to observe whether it can improve the cognitive function of VD rats,and to explore its role in Silent information regulation protein 1(SIRT1)/Forkhead-box transcription factor O3a(FoxO3a)pathway.Methods:The clean-grade adult healthy male Sprague-Dawley rats as experimental animals,weighing 250±50g,were randomly divided into sham operation group(sham group),VD model group(model group),resveratrol low-dose treatment group(30mg/kg,RSV-L group)and resveratrol high-dose treatment group(60mg/kg,RSV-H group)4 groups.The BCCAO method was used to establish a VD rat model.It should be noted that the rats in the sham operation group only separated their bilateral common carotid arteries without ligation.The next day after surgery,rats in the treatment group were given corresponding doses of resveratrol by gavage for drug intervention.Rats in the sham operation group and VD model group were given equal volumes of sodium carboxymethylcellulose solution by gavage,1 day times,lasting 28 days.The day after the administration,the Morris water maze experiment(including the positioning navigation experiment and the space exploration experiment)was used to detect the learning and memory ability of the rats in each group.Subsequently,appropriate materials were collected,and HE staining was used to observe the changes in the morphological structure of neurons in the CA1 region of the hippocampus of each group;Terminal deoxynucleotidyl transferase-mediated d UTP-biotin nick end labeling(TUNEL)to observe the apoptosis of neurons in the hippocampal CA1 area of each group of rats;Western blot detects the expression of SIRT1,FoxO3 a,Bcl2,Bax,LC3,Beclin1 protein in the hippocampus of each group.Results:1 Morris water maze resultsIn the positioning navigation experiment,the training days of the four groups of rats(F=59.86,P<0.01)and the comparison between groups(F=10.579,P<0.01)were statistically significant,while the interaction between training days and groups(F=0.736,P>0.05)was not statistically significant;compared with the sham operation group,the escape latency of rats in the VD model group was significantly prolonged(P<0.05 on day 1-5);compared with the VD model group,the escape latency of rats in the RSV-L group was significantly shortened(P>0.05 on day 1,P<0.05 on day 2-5),and the escape latency of rats in RSV-H group was shortened(P>0.05 on day 1-2,P<0.05 on day 3-5),the difference between RSV-L group and RSV-H group was not statistically significant(P>0.05).In the space exploration experiment,compared with the sham operation group,rats in the VD model group had a significantly lower percentage of stay time in the target quadrant(P<0.05);compared with the VD model group,the percentage of stay time in the target quadrant in the RSV treatment group increased(P<0.05),there was no significant difference between RSV-L and RSV-H groups(P>0.05).2 HE staining resultsThe morphological structure of neurons in the CA1 area of the hippocampus of rats in the sham group was complete,and the nuclei were large and round,and the nucleoli were clear.Compared with the sham group,the neurons in the CA1 region of the hippocampus of the model group were loosely arranged,the nucleus was pyknotic,and the remaining nucleoli were unclear or disappeared.After RSV treatment,the above situation improved,the neuron structure was more complete,the nucleus pyknosis was reduced,and the cell loss was reduced.3 TUNEL resultsThe apoptosis of neurons in the hippocampus CA1 area of the sham group was not obvious,and a large number of apoptotic neurons were seen in the model group,the percentage of neuronal apoptosis increased by 2.07 times in the model group compared with the sham group,and the difference was statistically significant(P<0.05).After RSV intervention,neuronal apoptosis was reduced,the percentage of neuronal apoptosis decreased and the difference was statistically significant(P<0.05),but there was no statistically significant difference in neuronal apoptosis between the high and low-dose groups(P>0.05).4 Western Blots4.1 The expression of SIRT1/FoxO3 a pathway protein in each group of ratsCompared with the sham group,the expression of SIRT1 and FoxO3 a protein in the hippocampus of the model group was decreased(P<0.05,P<0.05).After RSV treatment,the expression of SIRT1 and FoxO3 a protein in VD rats increased(P<0.05,P<0.05).4.2 Expression of apoptosis-related proteins Bcl-2 and Bax in each group of ratsCompared with rats in the sham group,the expression of the anti-apoptotic protein Bcl-2 in the model group was reduced(P<0.05),the pro-apoptotic protein Bax was significantly increased(P<0.05),and the Bcl2/Bax ratio decreased(P<0.05).After RSV treatment,the expression of Bcl-2 protein in the RSV-L group increased(P<0.05),the expression of Bax decreased(P<0.05),and the ratio of Bcl2/Bax increased(P<0.05);Bax protein in the RSV-H group decreased(P<0.05),and the ratio of Bcl2/Bax increased(P<0.05).4.3 The expression of autophagy-related proteins LC3Ⅱ/ and Beclin1 Ⅱin each group of ratsCompared with the sham group,the LC3Ⅱ/I ratio of the model group was reduced(P<0.05),and the expression of Beclin1 protein was reduced,but the difference was not statistically significant(P>0.05).After RSV treatment,the LC3Ⅱ/I ratio and Beclin1 protein expression of VD rats increased(P<0.05,P<0.05),and there was no significant difference between RSV-L group and RSV-H group(P>0.05).Conclusions:Resveratrol may inhibit hippocampal neuronal apoptosis and regulate neuronal autophagy by activating the SIRT1/FoxO3 a pathway to improve spatial learning,memory impairment and hippocampal pathological damage in VD rats. |
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