盐酸戊乙奎醚抑制脂多糖性肺损伤大鼠肺泡II型上皮细胞损伤和ERK活化

目的： 观察盐酸戊乙奎醚(PHC)对脂多糖(LPS)性肺损伤(ALI)大鼠肺泡II型上皮细胞(ATII)和肺组织细胞外信号调节激酶（ERK）活化的影响。 方法： SD大鼠随机分为对照组、LPS组（静脉注射5 mg/kg LPS）和LPS+PHC高、中、低(3.0、1.0和0.3 mg/kg)3个剂量组，每组8只，测定肺湿重/干重（W/D）比值，考马斯亮蓝法测BALF蛋白含量，双缩脲法测血浆蛋白含量，并计算肺通透指数（LPI=BALF蛋白/血浆蛋白），透射电镜观察各组ATII超微结构，并进行PHC影响肺组织ERK表达的量效性分析；另取大鼠在注入生理盐水（NS）后即刻0 h（对照组）和注射LPS后2 h、4 h、6 h和12 h共5个时点，每时点6只，进行PHC影响肺组织ERK表达的时效性分析。蛋白免疫印迹法检测肺组织ERK的表达。 结果： LPS组大鼠电镜下可见ATII板层小体排空明显而致空泡化，微绒毛脱落，微丝模糊、断裂、缩短，线粒体空泡变性，基膜不完整，而PHC显著减少ATII板层小体空泡化，减轻ATII损伤。LPS模型组大鼠肺W/D比值、LPI及肺组织磷酸化ERK表达显著高于对照组（均P＜0.05)，PHC高剂量组显著降低LPS诱导的大鼠肺W/D比值、LPI（均P＜0.05)，显著抑制LPS诱导的大鼠肺组织磷酸化ERK表达（P＜0.05)；PHC在LPS注射后6h时最能有效抑制ERK磷酸化。结论： PHC抑制LPS诱导的ALI大鼠肺组织通透性增加、ATII损伤和肺组织ERK活化，PHC对LPS诱导大鼠肺组织通透性增高和ATII损伤的拮抗作用可能与抑制ERK活化有关。

PHC inhibits the defects of alveolar type II epithelial cells and activation of ERK in lung tissue of ALI rat induced by LPS

AIM: To investigate the effects of penehyclidine hydrochloride (PHC) on lipopolysaccharide (LPS) induced the changes of ultrastructure of alveolar type II epithelial cells (ATII) and activation of extracellular signal-regulated protein kinase (ERK) in lung tissue in rats. METHODS: Acute lung injury (ALI) was induced successfully by intravenous administration of LPS (5 mg/kg) in rats. PHC (3.0, 1.0, and 0.3 mg/kg) was administered to rats 0.5 h prior and then again concomitant with LPS exposure. The changes of ultrastructure of ATII, lung permeability index (LPI), wet to dry weight (W/D) ratio in lung were measured at 6 h after LPS application. Western blotting analysis was performed to determine the phosphorylations of ERK in lung tissue at 6 h after LPS application. To examine whether the effects of PHC on activation of ERK was in a time-dependent manner, lung tissues at 0 h, 2 h, 4 h, 6 h, and 12 h were collected for measuring the level of phosphorylated ERK. RESULTS: Challenge with LPS alone resulted in a significant increase in W/D ratio in lung and LPI. The defects of ATII with no lamellar bodies in cytoplasm, the lack of microvilli along its margin, severely swollen endoplasmic reticulum, nuclear cisterna and loss of integrity of the basement membrane induced by LPS were observed under transmission electron microscope. LPS also triggered activation of ERK at 2 h. Pre-treatment with PHC significantly abolished increase in W/D ratio in lung, LPI and attenuated pathological changes of ATII in a dose-dependent manner. Moreover, pre-treatment with PHC efficiently blunted the activation of ERK induced by LPS at 6 h. CONCLUSION: These results suggest that pre-treatment with PHC significantly attenuates the lung permeability and defects of ATII in LPS-induced ALI in rats, and these effects are partly responsible for the inhibition of ERK activation by LPS.