大鼠脑缺血再灌注后GRP78、CHOP表达变化

The dysfunction of GRP78 and CHOP in rats with ischemic reperfusion injury

目的研究Wistar大鼠脑缺血2 h再灌注不同时间点葡萄糖调节蛋白78(GRP78)及C/EBP环磷酸腺苷反应元件结合转录因子同源蛋白(CHOP)的表达变化。方法选体质量(240±10)g Wistar大鼠,分别在缺血2 h、缺血2 h再灌注2 h、缺血2 h再灌注12 h、缺血2 h再灌注24 h时间点进行取材,随机抽取成功大鼠模型进行TTC染色证明模型成功,Western blot检测不同时间点GRP78及CHOP的表达,TUNEL技术检测大鼠模型损伤侧以及对侧细胞凋亡的数量。结果与正常组相比,成功模型在缺血2 h引起GRP78(P<0.001)及CHOP(P<0.05)表达升高,且GRP78和CHOP的升高点不完全重合。与自身健侧相比,个别模型健侧脑组织CHOP明显升高,然而GRP78未升高。与健侧相比,损伤侧TTC染色梗死面积增大(P<0.001),损伤侧TUNEL染色显示凋亡细胞多(P<0.001);健侧TTC染色正常,同时健侧TUNEL染色为阴性。结论在缺血相同时间内再灌注不同时间GRP78和CHOP升高不一致,细胞受到短时间的缺血再灌注损伤,显示GRP78表达持续上升,当细胞受到长时间的缺血再灌注时,GRP78虽然高表达,但细胞2017-12-18接收已经发生了凋亡坏死。本研究显示短时间细胞受损后GRP78与CHOP共同表达时能促进细胞的凋亡。

Objective To study the effects of reperfusion on glucose-regulated protein 78（ GRP78） and CCAAT/enhancer binding proteins homologous protein（ CHOP） in Wistar rats at different time points after 2 h cerebral ischemia. Methods Wistar rats（ 240 ± 10） g were divided into 4 groups： 2 h after ischemia,reperfusion 2 h after ischemia,reperfusion 12 h after ischemia,reperfusion 24 h after ischemia. Time point was randomly selected from the successful rat model proved by the TTC staining. The expression of GPR78 and CHOP was detected by Western blot at different time points. TUNEL technique was used to detect the number of apoptotic cells on the injured side and contralateral side of the rat model. Results Compared with the normal group,the successful model had an increase of GRP78（ P〈0. 001） and CHOP（ P〈0. 05） after 2 h ischemic injury,and the increasing points of GRP78 and CHOP were not completely coincident. Compared with the healthy side,the CHOP in the contralateral brain tissue of the individual models increased significantly,but this phenomenon did not appear in GRP78. Compared with the uninjured side,the infarct size increased by TTC staining on the injured side（ P〈0. 001）,and apoptotic cells increased by TUNEL staining on the injured side（ P〈0. 001）,while the uninjured side TTC did not,and the contralateral TUNEL stain was negative. Conclusion GRP78 and CHOP increase at different time of ischemic reperfusion injury. GRP78 is increased after short time of ischemic reperfusion injury,when the cells are subjected to prolonged ischemia reperfusion,and GRP78 is highly expressed,but the cells are under apoptotic and necrosis situation. In this experiment,we found that GRP78 co-expression with CHOP after a short period of cell damage can promote cell apoptosis.