大黄苷及苷元对脑缺血损伤大鼠自由基代谢的影响

Effects of glucoside and aglycone parts of rhubarb on the metabolism of free radicals in rats with ischemic brain injury

目的:从对自由基代谢的影响方面探讨大黄中苷及苷元等有效成分对脑缺血损伤的保护作用机制。方法:选用120只SD雄性大鼠,线栓阻塞大鼠大脑中动脉制备局灶性脑缺血模型,观察脑缺血损伤大鼠的神经症状改变,测定脑组织含水量、脑组织病理及钙离子含量;观察其血清和脑组织超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量的变化以及大黄有效成分对上述变化的影响。结果:模型组大鼠的神经症状评分、脑组织含水量及钙离子含量均显著增高,病理损伤明显、正常神经元细胞数目减少;大黄苷和苷元可显著降低神经症状分、脑组织含水量及钙离子含量,增加正常神经元细胞数目。模型组大鼠的血清、脑组织SOD活性显著降低,其值分别为(147.21±2.27)NU/mL和(60.96±6.82)NU/mg蛋白,尼莫地平组、大黄粉组、大黄苷及苷元各剂量组大鼠脑组织SOD活性显著增高,大黄苷高剂量组、大黄苷元高剂量组SOD活性[其值分别为(90.01±15.79),(101.33±10.41)NU/mg蛋白]较尼莫地平组、大黄粉组增高[其值分别为(88.04±14.76),(85.69±13.14)NU/mg蛋白];模型组大鼠的血清、脑组织MDA含量显著增高,大黄粉组、大黄苷(高、低)、大黄苷元各剂量组脑组织MDA含量较模型组下降明显,其中大黄苷元高剂量组脑组织的MDA含量下降[为(7.64±4.55)NU/mg蛋白]较大黄?

AIM:To study the mechanism of rhubarb effective components glucoside and aglycone in protecting against cerebral injury from the influence on the metabolism of free radical. METHODS: Totally 120 male SD rats were made in to focal cerebral ischemic model with the method of middle artery occlusion with nylon thread.The changes of neural symptoms in the rats with cerebral ischemic injury were observed;the water contents, pathologic and Ca2+contents in brain tissue were determined;the changes of superoxide dismutase(SOD) activity and malondialdehyde(MDA) content in their serum and the effects of glucoside and aglycone were observed. RESULTS:In the model group, the score of neural symptoms,water and Ca2+contents in brain tissue were significantly increased,pathologic injury was obvious and the number of normal neurons was reduced.Glucoside and aglycone of rhubarb could significantly decrease the score of neural symptoms,water and Ca2+contents in brain tissue, increase the number of normal neurons.The SOD activity in serum and brain tissue of rats in the model group were significantly decreased,which were(147.21±2.27) NU/mL and (60.96±6.82) NU/mg protein respectively,while those in the nimodipine group,rhubarb powder group,all dose glucoside and aglycone of rhubar groups were significantly increased;The SOD activities in the high dose glucoside and aglycone of rhubar groups[(90.01±15.79) and (101.33±10.41) NU/mg protein] were increased as compared with those in the nimodipine group and rhubarb powder group[(88.04±14.76) NU/mL and(85.69±13.14) NU/mg protein].The MDA contents in serum and brain tissue of the rats in the model group were significantly increased, the MAD content in brain tissue in the rhubarb powder group,high and low dose rhubar glucoside groups,all dose rhubar aglycone groups were all obviously decreased as compared with those in the model group,and the MDA content in brain tissue in the high dose rhubar aglycone group[(7.64±4.55) NU/mg per protein] was significantly decreased as compared with that in the rhubarb powder group[(14.14±7.78) NU/mg per protein]. CONCLUSION:Rhubarb's glucoside and aglycone parts have the significant protective effects on cerebral ischemic injury.The imbalance of free radical metabolism is involved in the process of cerebral ischemic injury, glucoside and aglycone can regulate the imbalance of free radical metabolism caused by cerebral ischemia,and then protect brain against cerebral ischemic injury.