目的 探讨蛋白激酶在大鼠缺血及再灌注脑损伤中的调节作用。方法 孕18 d SD大鼠,取胚胎大鼠海马并分离培养海马神经元,加阿糖胞苷抑制神经胶质细胞增殖以纯化神经元,随机分为对照组与实验组,对照组正常培养,实验组缺血时间设定为30 min与60 min,采用Western blot检测蛋白激酶C活性及蛋白表达。结果 对照组、实验组缺血30 min和缺血60 min神经元胞浆PKC活性分别为(6.24±0.27)pmol/(min·mg)、(3.26±0.21)pmol/(min·mg)和(3.05±0.17)pmol/(min·mg),胞膜PKC活性为(2.63±0.13)pmol/(min·mg)、(8.85±0.32)pmol/(min·mg)和(10.63±0.35)pmol/(min·mg),缺血神经元胞浆PKC活性较正常明显下降,胞膜PKC活性明显增加;缺血再灌注损伤后,其胞浆PKC活性分别为(0.97±0.19)pmol/(min·mg)和(0.82±0.16)pmol/(min·mg),胞膜PKC活性为(12.38±0.39)pmol/(min·mg)和(12.66±0.99)pmol/(min·mg),上述改变依然存在并较前者明显。PKCα表达亦呈现上述相似的改变。所有改变均随着缺血时间的延长而加重,与对照组比较,差异有统计学意义(P<0.05)。结论 缺血损伤与PKC的移位激活密切相关,缺血损伤所致的Ca2+超载为其中心环节。
Abstract
Objective To explore the modulation of protein kinase during ischemia/reperfusion brain injury.Methods Primary hippocampal cultures were prepared from day-18 SD rat embryos. Hippocampal neurons were dissociated by incubation in typsin and purified with arabinosylcytosin (Ara-c), which could inhibit the proliferation of neuroglia. The postischemia time was simplified to 30 min and 60min. Changes of PKC activity in plasma and membrane were assessed by phosphoryl transfer pieces and the expression of PKCα protein was measured by Western blot.Results The activities of cytosolic PKC of the control group, ischemia 30 min group and ischemia 60 min group were (6.24±0.27) pmol/(min·mg), (3.26±0.21) pmol/(min·mg) and (3.05±0.17) pmol/(min·mg)respectively, while the activities of membrane PKC were (2.63±0.13) pmol/(min·mg), (8.85±0.32) pmol/(min·mg)and(10.63±0.35) pmol/(min·mg)respectively. After ischemia/reperfusion brain injury , the activities of cytosolic PKC were (0.97±0.19) pmol/(min·mg)and (0.82±0.16) pmol/(min·mg)respectively, while the activities of membrane PKC were (12.38±0.39) pmol/(min·mg)and (12.66±0.99) pmol/(min·mg)respectively. Ischemia and reperfusion injury significantly increased the activity of membrane PKC and decreased that of cytosolic PKC. These changes became more significant with the extension of ischmia duration. Similar results were also observed in the expression of PKCα protein.Conclusions Ischemia reperfusion injury of rats’ hippocampal neurons results in translocational activation of PKC, especially PKCα, and the activation might damage the neurons by promoting calcium overload.
关键词
脑缺血 /
再灌注损伤 /
蛋白激酶
Key words
ischemia brain injury /
reperfusion injury /
protein kinase
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