姜黄素对缺血／再灌注大鼠海马神经细胞凋亡及NR2A、NR2B表达的影响

Effects of curcumin on the expressions of NR2A,NR2B and apoptotic neurons in hippocampus after ischemia-reperfusion in rats

目的观察不同剂量姜黄素对大鼠全脑缺血/再灌注后海马神经细胞凋亡及N-甲基-D-天门冬氨酸受体亚单位NR2A、NR2B表达的影响。方法采用SD大鼠四血管阻断模型,动物随机分为5组:假手术组(SH组)、缺血/再灌注组(I/R组)、姜黄素30、100、300mg·kg-1组(Cur30、100、300组),每组根据再灌注不同时间点(2h、6h、1d、3d、7d)又分5个亚组。HE染色观察海马神经细胞形态;TUNEL法检测海马CA1区神经细胞凋亡;免疫组化检测NR2A、NR2B蛋白在海马CA1区及CA3/DG区的表达。结果I/R组凋亡细胞多于SH组及Cur100组,Cur300组凋亡细胞多于Cur100组。姜黄素处理各组及SH组各时间点CA1区、CA3/DG区NR2A的表达均高于I/R组(P<0.05)。SH组及Cur100组CA1、CA3/DG区各时间点NR2B表达低于I/R组(P<0.05)。结论姜黄素减少缺血性神经细胞凋亡的发生可能与增加NR2A、降低NR2B蛋白表达有关;100mg·kg-1姜黄素抗凋亡作用最佳。

Aim To investigate the effect of curcumin on the expressions of NR2A, NR2B and apoptotic neurons in hippocampus after global brain ischemia-reperfusion in SD rats. Methods Global ischemic model induced by 4-vessel occlusion was adopted. Rats were randomly divided into 5 groups ： sham group （SH） , ischemia-reperfusion group （I/R） , curcumin 30 （ Cur 30）, 100 （Cur 100） and 300 mg · kg^-1 group （Cur 300）. At different time points after ischemia, animals were designated as subgroups 2 h, 6 h, 1 d, 3 d, 7 d. Cell morphology was observed on HE stain slides. The apoptotic neurons were detected in CA1 region by TUNEL method. Expressions of NR2A and NR2B in hippocampal CA1 and CA3/DG regions were detected by Immunohistochemical technique. Results At each time point the number of apoptotic neurons was much more in I/R group than that in SH group and Cur 100 group , and in Cur 300 group than that in Cur 100 group. The expression of NR2A was higher in the hippocampal CAI and CA3/DG regions in Cur 100 , Cur 300, Cur 30 and SH groups than that in I/R group at each time point（P 〈0. 05）. The expression of NR2B in I/R group in the hippocampal CA1 and CA3/DG regions was much higher than that in SH and Cur 100 groups （P 〈 0. 05 ）. Conclusions Curcumin can reduce the number of apoptotic neurons caused by I/R. Increasing the expression of NR2A and decreasing the expression of NR2B may be the protective mecha- nisms. Curcumin 100 mg · kg^-1 has the best anti-apoptotic effect.