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目的 :探讨增生细胞核抗原 ( Proliferating cell nuclearantigen PCNA)在老龄大鼠局灶性脑缺血后不同时空表达改变的规律。方法 :采用 2 6月龄 Wistar大鼠 ,在光化学诱导局灶性脑缺血后 ,应用免疫组织化学和原位杂交的方法从蛋白质和 m RNA水平观察不同时间和空间状态下 PCNA表达的改变。结果 :缺血 4小时缺血周边区有少许核染色为棕褐色颗粒的神经元和大量的胶质细胞 ;缺血 2 4小时在缺血中心区仍无 PCNA的表达 ,在缺血周边区则 PCNA表达较 4小时组增强 ( P<0 .0 1 )。缺血 5天组缺血周边区 PCNA表达则较 4小时明显减弱 ( P<0 .0 5)。除了缺血 4小时组缺血中心区及周边区其 m RNA水平较对照组增加 ( P<0 .0 5)外 ,其余各时间点基本和蛋白表达水平的改变相一致。结论 :脑缺血后衰老神经细胞 DNA损伤后存在切除修复现象 ,其修复能力的减弱参与了衰老神经元缺血后的死亡机制。
Objective: To investigate the regularity of Proliferating cell nuclearantigen (PCNA) in different temporal and spatial expression in aged rats after focal cerebral ischemia. Methods: Twenty-six-month-old Wistar rats were used to observe the changes of PCNA expression at different time and space conditions by immunohistochemistry and in situ hybridization after photochemical focal cerebral ischemia. Results: In the ischemic 4 hours after ischemia, there were a few nuclei stained brown granules and a large number of glial cells. In the ischemic 24 hours, there was no PCNA expression in the ischemic center, PCNA expression increased compared with 4 hours (P <0.01). The expression of PCNA in the ischemic peripheral area on the 5th day after ischemia was significantly weaker than that on 4 hours (P <0.05). In addition to ischemia 4 hours ischemic center and peripheral areas of its m RNA levels increased compared with the control group (P <0. 05), the rest of the time point basic and protein expression level changes consistent. Conclusion: There is resection and repair after DNA damage in aged neurons after cerebral ischemia, and their weakened ability of repair is involved in the death mechanism of neurons after aging.