Savithiry S, Kumar K
Department of Pathology, Michigan State University, East Lansing 48824.
Mol Chem Neuropathol. 1994 Jan;21(1):1-11. doi: 10.1007/BF03160080.
To investigate the role of Ca(2+)-independent forms of protein kinase C (PKC) in ischemic neuronal injury, mRNA expression of PKC was studied by Northern blot analysis. Ischemia was produced in gerbils by 10-min bilateral carotid artery occlusion and was followed by recirculation for 15 min, 6 h, and 24 h. Brains of postischemic and sham-operated animals were removed, forebrains fresh frozen, and processed for Northern blot analysis. Three synthetic oligonucleotide probes based on published cDNA sequences of rat brain PKC for the isozymes delta, epsilon, and zeta were utilized for hybridization. Northern blot analysis showed increased hybridization signal for all three PKC isozymes examined in the 6- and 24-h postischemic groups. Of these, the twofold increases in the expression of PKC delta and zeta were statistically significant in comparison to the control. These results suggest that the mRNA levels of Ca(2+)-independent forms of PKC, in particular, delta and zeta, are temporally stimulated by ischemic injury in the brain and may imply an important role of the enzyme in postischemic neuronal damage. However, since the protein itself was not examined in this study, the significance of the increased expression cannot be ascertained. However, it may reflect a compensatory response to the loss of PKC reported to occur in the reperfusion phase.
为研究非钙依赖性蛋白激酶C（PKC）在缺血性神经元损伤中的作用，采用Northern印迹分析法研究PKC的mRNA表达。通过10分钟双侧颈动脉闭塞在沙鼠中造成缺血，随后再灌注15分钟、6小时和24小时。取出缺血后和假手术动物的大脑，将前脑新鲜冷冻，并进行Northern印迹分析。使用基于已发表的大鼠脑PKC同工酶δ、ε和ζ的cDNA序列合成的三种寡核苷酸探针进行杂交。Northern印迹分析显示，在缺血后6小时和24小时组中，所检测的所有三种PKC同工酶的杂交信号均增加。其中，与对照组相比，PKCδ和ζ表达增加两倍具有统计学意义。这些结果表明，非钙依赖性PKC同工酶，特别是δ和ζ的mRNA水平在脑缺血损伤后受到时间性刺激，这可能意味着该酶在缺血后神经元损伤中起重要作用。然而，由于本研究未检测蛋白本身，因此无法确定表达增加的意义。不过，这可能反映了对据报道在再灌注阶段发生的PKC丢失的一种代偿反应。
