人参皂甙Rb1通过促肺泡细胞线粒体自噬以抑制凋亡在大鼠肺气肿模型治疗的机制

Mechanism of ginsenoside Rb1 in treatment of rat with emphysema by promoting mitochondrial autophagy of alveolar cells to inhibit apoptosis

目的观察人参皂甙Rb1(GS-Rb1)对大鼠肺气肿的治疗作用是否与自噬的的促进及对凋亡的抑制相关。方法选取40只体重150~200克的SD雄性大鼠随机分为4组,每组10只,以气管内注射猪胰蛋白酶(PPE)建立肺气肿型,腹腔注射给予GS-Rb1及自噬抑制剂氯喹(CLQ)。具体分组为:①阴性对照(Control)组、②治疗(PPE+GS-Rb1)组、③阻断(PPE+GS-Rb1+CLQ)组、④肺气肿组(PPE)组。留取支气管肺泡灌洗液(Bronchoalveolar lavage fluids,BALF)测定其中白细胞数量,采用酶联免疫荧光(ELFA)检测神经元氧化应激因子NAPDH氧化酶活性的变化,同时取肺泡组织,HE染色观察病理学变化、蛋白免疫印记法(WB)测定自噬相关蛋白LC3-Ⅱ、LC3-Ⅰ、P62,线粒体功能蛋白PGC-1a、mtTFA及凋亡相关蛋白Cyto C、Bax、Bcl-2的变化。结果实验结果显示,治疗组较肺气肿组的肺泡组织病理学损伤程度明显好转,NAPDH氧化酶活性及BALF中白细胞总数、中性粒细胞百分比明显下降(P<0.05),同时治疗组相对于肺气肿组的自噬相关蛋白LC3-Ⅱ/LC3-Ⅰ比例升高、P62表达下降,线粒体功能蛋白PGC-1a、mtTFA上调,凋亡促进因子Cyto C及Bax表达明显降低,而凋亡抑制因子Bcl-2表达则明显升高(P<0.05)。采用自噬抑制剂CLQ可明显抑制上述GS-Rb1通过自噬抑制凋亡从而缓解慢阻肺的病理改变、下调BALF中细胞数、中性粒细胞百分比及NAPDH氧化酶活性的功效,(P<0.05)。结论GS-Rb1可能通过促进肺泡细胞线粒体自噬而抑制凋亡途径进而抑制损伤性因子的产生,以达到对肺气肿的治疗作用。

Objective To observe whether the therapeutic effect of ginsenoside Rb1(GS-Rb1)on emphysema in rats is related to the promotion of autophagy and the inhibition of apoptosis.Methods 40 SD male rats weighting 150~200 g were randomLy divided into 4 groups,10 in each group.Porcine trypsin(PPE)was injected into trachea to establish emphysema type,and GS-Rb1 and the autophagy inhibitor chloroquine(CLQ)was injected into abdomen.The specific four groups included the control group,the treatment(PPE+GS-Rb1)group,the block(PPE+GS-Rb1+CLQ)group,and the emphysema group(PPE)group.Bronchoalveolar lavage fluids(BALF)were used to determine the number of white blood cells,and the NAPDH oxidase activity was determined by ELFA.Meanwhile,the alveolar tissues were collected,part of tissues were stained with HE for observation of pathological of emphysema,and the other tissues were tested for the examination of autophagy related proteins LC3Ⅱ,LC3Ⅰand P62,mitochondrial functional proteins PGC-1 a,mtTFA,and apoptosis-related proteins Cyto C,Bax and Bcl-2 by WB.Results The experimental results showed that the pathological injury of alveolar organizations improved more pronounced,and the total number of leukocytes,percentage of neutrophils,NAPDH oxidase activity in BALF decreased more obviously in the treatment group than in the emphysema group(P<0.05).At the same time,the ratio of autophagy related proteins LC3Ⅱ/LC3Ⅰincreased,P62 expression decreased,mitochondrial function protein PGC-1a,mtT FA rise,apoptosis promoting factor Cyto C and Bax expression decreased,and apoptosis inhibiting factor Bcl-2 expression increased more significantly in the treatment group than in the emphysema group(P<0.05).The level of emphysema was alleviated by GS-Rb1(P<0.05).The use of autophagy inhibitor CLQ could significantly inhibit the above GS-Rb1 inhibition of apoptosis by autophagy,as well as the down-regulation of the number of cells in BALF,the percentage of neutrophils and the activity of NAPDH oxidase(P<0.05).Conclusion GS-Rb1may inhibit the apoptosis pathway by promoting mitochondrial autophagy in alveolar cells,thereby inhibiting the production of injury factors,so as to achieve the therapeutic effect on emphysema.