趋化因子受体CCR2在新生鼠实验性缺氧缺血损伤脑组织中的表达

目的 观察新生鼠实验性缺氧缺血性脑损伤(HIBD)后脑组织趋化因子受体2(CCR2)mRNA与蛋白质水平的表达变化,探讨其在HIBD中的作用.方法 采用结扎7 d龄SD大鼠右侧颈总动脉并暴露于8%氧气环境2.5 h制作HIBD模型, 用TaqMan实时荧光定量逆转录聚合酶链反应和SDS-PAGE免疫印迹方法,动态定量监测大脑皮质、海马区脑组织中CCR2 mRNA与蛋白质表达水平在HIBD后不同时间点的变化, 假手术组为对照组.结果 HIBD后24 h右侧脑组织CCR2 mRNA水平最高,72 h仍高于对照组(P＜0.05),7 d恢复至对照组水平(P＞0.05);CCR2蛋白表达量在HIBG后24 h最高,高于对照组(P＜0.05), 3 d仍保持高水平表达(P＜0.05),7 d明显下降.结论 HIBD后CCR2 mRNA及蛋白质表达水平显著升高,其动态变化过程与脑损伤发展过程一致,提示CCR2参与了新生动物HIBD的发生.

Expression of Chemokine Receptor CCR2 in Cerebral Tissue of Newborn Rat with Experimental Hypoxic-ischemic Brain Damage

Objective To observe the expressions of mRNA and protein for the CCR2 in cerebral tissue with experimental hypoxic-ischemic brain damage (HIBD) to newborn rat. Methods The HIBD model of SD rat was set up by ligating the right carotid artery and exposing the animals to 8% oxygen for 2.5 h. The dynamic change of CCR2 mRNA level was studied by using quantitative, real-time, fluorescence PCR assay (TaqMan), and the change of CCR2 protein was detected by SDS-PAGE assay. Results The highest expression of CCR2 mRNA was showing at 24 h after HIBD, of which the level was significantly higher in hypoxic-ischemic (HI) cerebral hemisphere than in control(P<0.05). The CCR2 mRNA level of 72 h after HIBD was still higher than that of control (P>0.05) but had no difference on 7 d after HIBD when compared with control (P>0.05). The increased expression of CCR2 protein was detected at 12 h after HIBD and peaked at 24 h after HIBD. The significant increase of CCR2 protein persisted in HI hemisphere up to 3 d after HIBD. Conclusion The expressions of CCR2 mRNA and protein increase significantly in cerebral tissue of newborn rat with HIBD. The dynamic change of CCR2 expression is consistent with the process of HIBD, which suggests that CCR2 expression after HIBD may play an important role in the mechanism of brain damage.