黄芪对脂多糖致急性肺损伤的保护机制

Protective Effect of Astragali on LPS-induced Acute Lung Injury

目的:研究脂多糖(LPS)致大鼠急性肺损伤(ALI)后大鼠肺组织损伤和细胞凋亡情况及黄芪的保护作用。方法:雄性Wistar大鼠30只随机分成3组:对照组、ALI组和黄芪组。采用颈外静脉注射脂多糖5 mg／kg形成急性肺损伤的动物模型,对照组注射0．9％氯化钠,黄芪组在注射LPS后30 min注射黄芪注射液。观察各组呼吸频率和动脉血氧分压及肺组织湿／干(W／D)比值;电镜观察肺组织的超微结构;采用放射免疫法检测血浆肿瘤坏死因子-α(TNF-α)和白介素-1β(IL-1β)的浓度;并同时用原位末端转移酶标记 (TUNNEL)法和透射电镜观察肺泡上皮细胞凋亡情况。结果:ALI组大鼠出现呼吸窘迫和低氧血症,肺水肿严重,W／D比值显著升高,血浆TNF-α和IL-1β浓度亦显著升高,电镜显示肺组织内中性粒细胞(PMN)浸润较多,肺泡上皮细胞变性、空泡化,TUNNEL阳性细胞数较多。而黄芪组呼吸窘迫和低氧血症症状改善,肺水肿减轻,W／D比值,血浆TNF-α和IL1β浓度亦较ALI组显著下降,电镜示肺组织内中性粒细胞浸润相对较少,肺泡上皮细胞较完整,TUNNEL阳性细胞数减少。结论:黄芪能减轻LPS所致呼吸窘迫征状,减少肺组织内中性粒细胞浸润,保护肺泡上皮细胞,减轻肺水肿,减少促炎因子TNF-α、IL-1β的释放,抑制肺泡上皮细胞凋亡。

Objective： To observe the pulmonary injury ,apoptosis of pulmonary epithelium and the protective effect of astragali on lipopolysaccharide（LPS）-induced acute lung injury（ALI） in rats. Methods： The rats were randomly divided into three groups： control group, ALI group, astragali group. The respiratory rate, partial pressure of arterial oxygen, and the ratio of W/D were detected. TNF-α and IL-1βin blood plasma were measured, Pulmonary histopathological examinations were performed by electron microscope, apoptosis of pulmonary epithelium was detected by TUNNEL using immunocytochemistry in all groups. Results： Partial pressure of arterial oxygen in ALI group was lower significantly than that in control group. The respiratory rate, the ratio of W/D, the levels of serum TNF-αand IL-1β in ALI group were all significantly higher than those in control group. The PMNs infiltration in ALI group was more than that in control group and the integrity of the alveolus epithelium in ALI group was destroyed. TUNNEI;positive cells in ALI group were more than those in control group. In astragali group, partial pressure of arterial oxygen was higher significantly than that in ALI group. The respiratory rate, the ratio of W/D, the levels of serum TNF-αand IL-1βin ALI group were all significantly lower than those in ALI group. The PMNs infiltration was less than that in ALI group. TUNNEI;positive cells were less than those in ALI group. Conuslon：After administration of astragali, the symptoms of respiratory distress were reduced, the infiltration of PMN in pulmonary tissue and pulmonary edema were decreased, the release of TNF-α and IL-1β in blood plasma were reduced,the apoptosis of the pulmonary epithelium was inhibited. These suggest that astragali may have protective effects on LPS-induced ALI in rats.