目的 探讨香菇多糖对脓毒症肺损伤小鼠自噬的影响及作用机制。方法 将C57BL/6小鼠分为假手术组、模型组、香菇多糖（100 mg/kg）组、哺乳动物雷帕霉素靶蛋白（mammalian target of rapamycin，mTOR）通路激活剂MHY1485（10 mg/kg）组、香菇多糖＋MHY1485组，每组15只。除假手术组外，其他组均按照盲肠结扎穿孔法构建脓毒症模型。造模成功后，给予相对药物进行干预，假手术组和模型组ip等体积的生理盐水。末次给药24 h后，检测小鼠右肺中叶肺组织湿质量/干质量；ELISA法检测小鼠肺泡灌洗液中白细胞介素-1β（interleukin-1β，IL-1β）、IL-6和肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）水平；苏木素-伊红（HE）染色法检测肺组织病理变化；透射电子显微镜（TEM）观察肺组织中自噬小体的形成；Western blotting检测肺组织Beclin1、微管相关蛋白1轻链3（microtubule-associated protein 1 light chain3，LC3）、mTOR、磷酸化mTOR（phosphorylated mTOR，p-mTOR）、p70核糖体蛋白S6激酶（p70 ribosomal protein S6 kinase，p70S6K）和磷酸化p70S6K（phosphorylated p70S6K，p-p70S6K）蛋白表达情况。结果 与假手术组比较，模型组小鼠肺组织结构破坏，肺组织湿质量/干质量及肺泡灌洗液中IL-1β、IL-6、TNF-α水平和肺组织p-mTOR/mTOR、p-p70S6K/p70S6K蛋白表达水平显著升高（P＜0.05），自噬小体数量及肺组织Beclin1、LC3-II/LC3-I蛋白表达水平显著降低（P＜0.05）；与模型组比较，香菇多糖组小鼠肺组织损伤减轻，肺组织湿质量/干质量及肺泡灌洗液中IL-1β、IL-6、TNF-α水平和肺组织p-mTOR/mTOR、p-p70S6K/p70S6K蛋白表达水平显著降低（P＜0.05），自噬小体数量及肺组织Beclin1、LC3-II/LC3-I蛋白表达水平显著升高（P＜0.05），而MHY1485组小鼠肺组织损伤加剧，上述对应指标与香菇多糖组呈相反趋势（P＜0.05）；MHY1485可减弱香菇多糖对脓毒症小鼠肺损伤的保护作用。结论 香菇多糖可能通过抑制mTOR通路激活自噬来发挥对脓毒症肺损伤小鼠的保护作用。

Objective To investigate the effect and mechanism of lentinan on autophagy in septic lung injury mice. Methods C57BL/6 mice were divided into sham group, model group, lentinan (100 mg/kg) group, mammalian target of rapamycin (mTOR) pathway activator MHY1485 (10 mg/kg) group, lentinan + MHY1485 group, 15 rats in each group. Except for sham group, all other groups constructed sepsis models according to cecal ligation and perforation method. After the model was successfully built, the corresponding drugs were given for intervention, sham group and model group were ip same amount of normal saline. 24 h after the last administration, wet mass/dry mass of lung tissue in middle lobe of right lung of mouse was measured; ELISA method was used to detect interleukin-1β (IL-1β), (IL-6) and tumor necrosis factor-α (TNF-α) levels in alveolar lavage fluid of mice; HE staining was used to detect lung tissue pathological changes; Transmission electron microscopy (TEM) was used to observe the formation of autophagosomes in lung tissue; Western blotting was used to detect Beclin1, microtubule-associated protein 1 light chain 3 (LC3), mTOR, phosphorylated mTOR (p-mTOR), p70 ribosomal protein S6 kinase (p70S6K) and phosphorylated p70S6K (p-p70S6K) protein expression of lung tissue. Results Compared with sham group, lung tissue structure of mice in model group was destroyed, wet mass/dry mass of lung tissue, levels of IL-1β, IL-6 and TNF-α in alveolar lavage fluid, and protein expression levels of p-mTOR/mTOR, p-p70S6K/p70S6K in lung tissue were significantly increased (P < 0.05), number of autophagosomes and Beclin1, LC3-II/LC3-I protein expressions in lung tissue were significantly decreased (P < 0.05); Compared with model group, lung tissue damage of mice in lentinan group was reduced, wet mass/dry mass of lung tissue, levels of IL-1β, IL-6 and TNF-α in alveolar lavage fluid, and protein expression levels of p-mTOR/mTOR, p-p70S6K/p70S6K were significantly reduced (P < 0.05); The number of autophagosomes, and Beclin1, LC3-II/LC3-I protein expression in lung tissue were significantly increased (P < 0.05), while the lung tissue damage of mice in MHY1485 group was aggravated, and the corresponding indicators above showed an opposite trend to lentinan group (P < 0.05); MHY1485 attenuated the protective effect of lentinan on lung injury in septic mice. Conclusion Lentinan may play a protective effect on septic lung injury mice by inhibiting mTOR pathway and activating autophagy.

R285.5

2019年河南省医学科技攻关计划联合共建项目(LHGJ20190213)