| Objective: By observing the impact of the limb ischemia postconditioning of lithium chloride on glycogen synthase kinase 3β(GSK3β) and its downstream microtubule-associated protein 2(MAP2a / b). To investigate whether limb ischemia conditioning adopt GSK3β / MAP2 a / b signaling pathway in brain ischemia-reperfusion protection.Methods: Production of cerebral ischemia and reperfusion,limb ischemia postconditioning and intervention in rat model of lithium chloride. 60 Specific pathogen Free male SD rats(220-280g) were using random number table randomly divided into four groups, sham operation group(sham), ischemia-reperfusion(I / R group), limb ischemia postconditioning group(Lpost group), limb ischemia postconditioning + lithium chloride(GSK3β blocker) group(Li Cl group). I / R group: 2 hours ischemia, reperfusion 24 hours. Lpost Group: 2 hours ischemia, reperfusion 24 hours. At the same time reperfusion implement limb ischemia postconditioning, ischemic 5min, perfusion 5min 3 cycles in the femoral artery. Li Cl group: 20 min before reperfusion when injected intraperitoneally Li Cl 3mmol / kg, the same as the other dealing with Lpostgroups.Rats with cerebral ischemia and reperfusion 24 hours after dosing were observed behavior score changes,HE staining,pathological infarct volume,TUNEL measure brain cell apoptosis, westernblot measure rats P-GSK3β(ser9), MAP2 a / b expression, immunohistochemistry measures P-GSK3β(ser9), MAP2 a / b immunoreactive cells. Analysis whether the limb ischemia postconditioning by GSK3β/MAP2 a / b protect cerebral ischemia.Results: 1 neurological behavior score: neurological behavior score of sham-operated rats were zero, cerebral ischemia-reperfusion model group’s neurological deficit scores were the highest, limb ischemia postconditioning group had lower neurological deficit scores, lithium chloride group had the lowest neurological deficit scores, compared four group’s neurobehavioral scores were significant difference(P <0.05),2.ischemic parietal cortex(caudate nucleus plane) pathology: sham group had normal structure rat brain tissue. Ischemia-reperfusion group are large areas of necrosis,necrotic area without nerve cells.The extent of nerve cell degeneration and necrosis in limb ischemia postconditioning were light than ischemia-reperfusion group. and lithium chloride group of cell degeneration and necrosis were lighter than ischemia-reperfusion group and limb ischemia postconditioning group.3.the cerebral lesion volume of rat: Sham group rat brain tissue were without infarction lesions. Cerebral ischemia-reperfusion had largest infarct area and limb ischemia postconditioning had reduced infarct area than the former, both compared statistically significant difference(P <0.05), lithium chloride group had minimum infarct size, and compared withischemia-reperfusion group and the limb ischemia postconditioning group were statistically significant differences.(P <0.05),4.positive apoptotic cells in TUNEL experiment:sham group had a small number of apoptotic cells, as normal apoptotic cells.I / R group had increased significantly apoptotic cells.limb ischemia postonditioning had apoptotic cells statistically significant decrease three groups were statistically significant differences(P <0.05).Compared with I / R group,limb ischemia postconditioning group,Lithium chloride group reduced the number of apoptotic cells,the three groups were statistically significant. 5. in Western blotting experiment parietal brain ischemia side P-GSK3β(ser9) and MAP2a/b protein expression: sham group was expression of P-GSK3β(ser9) protein, I / R group brain P-GSK3β(ser9) protein expression in tissues was significantly reduced, increased expression of limb ischemia postconditioning group,P-GSK3β(ser9) protein expression up to lithium chloride group, the difference was statistically significant compared to the four groups(P <0.05). Sham group had the most MAP2a/b expression, MAP2a/b expression I / R group decreased.The expression limb ischemia postconditioning group increased,compared with limb ischemia postconditioning, lithium chloride group had the more MAP2a/b protein expression,there were statistically significant(P <0.05) compared to the four groups. 6. Immunohistochemical expression of P-GSK3β(ser9), MAP2 a / b immunoreactive cell number:Ischemia-reperfusion group only had a few positive cells express P-GSK3β(ser9), compared with the sham group, the difference was significant(P <0.05). Compared with the I / R group, Lpost C group, Li Cl groupP-GSK3β(ser9) immunoreactive cells gradually increased, compared to the three groups were significantly(P <0.05). There are a lot of MAP2a/b expression for normal nerve cells in sham group. Ischemia-reperfusion group only had a few MAP2a/b positive cells, compared with the sham group, the difference was significant(P <0.05). Compared with the I / R group, Lpost C group, Li Cl group MAP2a/b immunoreactive cells gradually increased, compared to the three groups were significantly(P <0.05). Conclusions: 1.limb ischemia postconditioning group can improve symptoms of neurological deficit, reduce pathological brain tissue damage, reduce infarct lesion volume, reduce apoptosis, increased expression of P-GSK3 β protein, MAP2 expression gradually increased, gradually increasing P- GSK3β(ser9), MAP2 a / b immunoreactive cells. limb ischemia postconditioning group can protect cerebral ischemia-reperfusion injury in rats. 2. cerebral ischemia and reperfusion reduce P-GSK3β(ser9), MAP2 a / b positive cells,limb ischemia postconditioning group increased P-GSK3β(ser9), MAP2 a / b positive cells, P-GSK-3β(ser9) is inactivated form. Limb ischemia postconditioning suppressed GSK3β / MAP2 a / b signaling pathway on brain ischemia and reperfusion protective effect. |
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