| Part1 Protective effect of Quercetin on Bupivacaine induced neurotoxicityObjective To identify the effect of quercetin on the bupivacaine induced neurotoxicity and to preliminarily investigate the underlying mechanism.Methods The SH-SY5Y cells were cultured and exposed to bupivacaine alone,quercetin alone,bupivacaine with quercetin,and bupivacaine with mibefradil.The effect of quercetin on bupivacaine induced neurotoxicity was investigated by the comparison of the cell morphology,the cell viability and the cell apoptosis with or without quercetin after exposed to bupivacaine;the underlying mechanism for the effect was preliminarily studied by comparing the cytosolic calcium ion concentration and Cav3.1 protein expression level in different drug treatment groups.Results There was no statistically significant difference in cell morphology,cell viability,apoptosis rate,intracellular calcium concentration and Cav3.1 protein expression level in the control group(C)and the Quercetin group(Q).The cell viability in the Bupivacaine group(B)was significantly lower than that in the control group(C),the cell apoptosis rate,intracellular calcium concentration and the Cav3.1 protein expression level were significantly higher than those in the control group(C)(P<0.01).The cell viability of quercetin combined with bupivacaine group(Q+B)and mibefradil combined with bupivacaine group(M+B)was significantly higher than that of the Bupivacaine group(B),the cell apoptosis rate,intracellular calcium concentration and Cav3.1 protein expression level were significantly lower than that of the bupivacaine group(B)(P<0.01).Conclusion The results indicated that an herbal medicine derived drug-quercetin could reduce the neurotoxicity induced by bupivacaine and it's possibly through the inhibition of T type calcium channel.The finding also suggested potential application of herbal medicine derived drugs for blocking T type calcium channel.Part 2 Effect of Quercetin on cerebral ischemia-reperfusion in rats and its possible mechanismObjective To identify the effect of quercetin on global cerebral ischemia-reperfusion injury in rats and to preliminarily investigate the underlying mechanism.Methods Seventy-two adult male Sprague-Dawley rats weighing 200?250 g were randomly divided into 3 groups(n=24 each):sham operation group(S),cerebral ischemia-reperfusion group(I/R)and qucertin group(Q).Global cerebral ischemia was induced by 20 min occlusion of bilateral common carotid arteries combined with hypotension(MAP maintained at 35-45 mmHg).In the quercetin group(Q)quercetin 20 mg/kg was injected intraperitoneally at 1h after reperfusion.In the other two groups the same volume of saline was injected intraperitoneally.Randomly taking 6 rats in each group,using platform test and Morris Water Maze experiment to determine the cognitive function of rats on the third day of reperfusion.The rats left in each group were sacrificed at 24 h of reperfusion,pathological changes in CA1 region of hippocampus was observed by HE staining and the number of apoptotic cells was measured by TUNEL staining;the water content in the brain was measured by calculating the ratio of dry weight to wet weight of the brain;the blood-brain barrier permeability in cerebral cortex was measured by fluorescence spectrophotometer and fluorescence microscopy for Evans Blue(EB)extravasation;the contents of tumor necrosis factor-a(TNF-a),interleukin-1 ?(IL-1?)and interleukin-10(IL-10)were assayed by the method of ELISA.Results In the comparison of S group,the I/R group had prolonged escape latency from the 1st to 5th day of the experiment,whereas the Q group had prolonged escape latency from the 1st to 3 rd day of the experiment.Both of the two groups had shortened 1st quadrant residence time.In the comparison of I/R group,the Q group had shortened escape latency and prolonged 1st quadrant residence time from the 1st to 5th day of the experiment.Compared with S group,the reaction time,the number of reaction errors,the number of avoidance errors of I/R group were increased,and the latent period was shortened.Compared with I/R group,the reaction time,the number of reaction errors,the number of avoidance errors of Q group were decreased,and the latent period was prolonged(P<0.01).Compared with S group,the damage of hippocampus CA1 area was obvious,the apoptosis index,EB content,water content and TNF-a and IL-1? content of brain tissue increased,and the content of IL-10 decreased in the other two groups.Compared with I/R group,the damage of hippocampus CA1 area was not obvious,the apoptosis index,EB content,water content and TNF-a and IL-1? content of brain tissue decreased,and the content of IL-10 increased in Q group(P<0.01).Conclusion Quercetin can improve the cognitive function of rats after global cerebral ischemia-reperfusion.It also can reduce permeability of blood-brain barrier and edema level of brain tissue which induced by global cerebral ischemia-reperfusion injury in rats,the mechanism may be explained by inhibition of inflammatory reaction. |
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