人参皂苷Rg1对D-半乳糖所致小鼠心肌损伤的保护作用

Protective effects of ginsenoside Rg1 on cardiac muscle of aging mice induced by D-galactose

目的探讨人参皂苷Rg1对D-半乳糖(D-galactose,D-gal)所致小鼠心肌损伤的保护作用和射D-gal(200 mg·kg^(-1)·d^(-1)×42 d);Rg1干预模型组:按D-gal损伤模型组小鼠处理,从建模第16天起腹腔注射Rg1(40 mg·kg^(-1)·d^(-1)×26 d);对照组:腹腔注射等量生理盐水42 d;Rg1对照组:按对照组处理小鼠16 d,再腹腔注射Rg1(剂量同Rg1干预模型组)。各组处理完成后第2天,取心脏测定脏器指数;石蜡切片,HE染色观察心肌组织病理学,透射电镜观察心肌纤维超微结构;酶标比色法检测心肌组织匀浆中谷草转氨酶(AST)、乳酸脱氢酶(LDH)、总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)活性和丙二醛(MDA)表达量;Western blot检测心肌组织中Nrf2、Keap1、HO-1蛋白表达。结果D-gal损伤模型组小鼠心脏指数明显升高(P<0.01);心肌纤维间胶原纤维沉积量增加;肌原纤维束排列紊乱,心肌纤维直径显著增大,线粒体形态异常伴有肿胀;心肌组织的AST、LDH活力显著升高,T-SOD、CAT活性显著降低,MDA表达量显著升高(P<0.05);Nrf2、HO-1蛋白表达量显著降低(P<0.05),Keap1蛋白表达量无显著变化。Rg1干预模型组小鼠心脏指数明显降低(P<0.01);胶原纤维沉积量减少,肌原纤维束排列较为整齐,心肌纤维直径与正常对照组相比无统计学差异,线粒体形态基本正常,无明显肿胀;AST、LDH活力显著降低,T-SOD、CAT活性显著升高,MDA表达量显著降低(P<0.05);Nrf2、HO-1蛋白表达量显著升高,Keap1蛋白表达量显著降低(P<0.01)。结论Rg1能有效拮抗D-gal对小鼠心肌组织结构和超微结构的损伤,其机制可能与抑制氧化应激和上调Nrf2抗氧化信号通路有关。

Objective To investigate the protective effects and primary mechanism of ginsenoside Rg1 on cardiac muscle of aging mice induced by D-galactose(D-gal).Methods C57 BL/6 J mice were randomlydivided into normal control, model, Rg1 intervention and negative control groups, with 10 animals in eachgroup. D-gal(200 mg/kg) was injected intraperitoneally to the mice for 42 d to establish the model group,and the mice of the Rg1 intervention group was given 40 mg/kg Rg1 per day for 26 d intraperitoneally from the16 th day of model establishment. The mice of the normal control group were given same amount of normalsaline for 42 d, and those of the negative control group were treated with normal saline after modelestablishment. On the 2 nd day after treatment, the hearts were taken to measure the organ index. HE staining and transmission electron microscopy were performed to observe the morphology and micro-structures of theheart tissue from each group. The activities of aspartate aminotransferase( AST), lactate dehydrogenase(LDH), total superoxide dismutase(T-SOD), catalase(CAT) and contents of malondialdehyde(MDA) inthe myocardial tissue homogenate were tested by enzyme-labeled colorimetry;The expression levels of Nrf2,Keap1 and HO-1 in the heart tissue were detected by Western blotting.Results Compared with the controlgroup, the model group had significantly increased heart index(P<0.01);larger amount of deposited collagenfibers between myocardial fibers, disordered myofibril bundles, thicker myocardial fibers, and abnormallyswollen mitochondria;enhanced AST and LDH activities, declined T-SOD and CAT activities, and increasedMDA content(P<0.05);remarkably down-regulation of Nrf2 and HO-1(P<0.05), and no changed Keap1 level. While in the Rg1 intervention group, all the above phenomena were greatly improved after theintervention, with obviously decreased heart index(P<0.01), not notable morphological changes with normalcontrol mice, reversed AST, LDH, T-SOD and CAT activities and MDA contents(P<0.05), and elevatedprotein levels of Nrf2 and HO-1, and decreased level of Keap1(P<0.01).Conclusion Rg1 effectivelyalleviates the damage of D-gal to the morphology and ultrastructure of mouse myocardium, and its mechanismmay be related to the inhibition of oxidative stress and the up-regulation of the Nrf2 antioxidant signalpathway.