雷帕霉素激活自噬流逆转脂多糖所致的急性肺损伤

Rapamycin reverse lipopolysaccharide-induced acute lung injury through activating autophagy flux

为探讨自噬对脂多糖(LPS)所致脓毒症小鼠急性肺损伤的影响,采用健康昆明小鼠随机分为空白组、模型组(LPS,10 mg/kg),雷帕霉素组(RAP,6 mg/kg),RAP-LPS组(RAP 6 mg/kg+LPS 10 mg/kg),3-甲基腺嘌呤组(3-MA,300μg/kg)和3-MA-LPS组(3-MA 300μg/kg+LPS 10 mg/kg),腹腔注射,给药6 h后,检测小鼠死亡率、肺组织中性粒细胞浸润、以及TNF-α、LC3和P62的表达。结果显示在LPS组中,小鼠肺组织中性粒细胞浸润显著增多,死亡率增加,TNF-α、LC3-Ⅱ和P62表达升高;RAP-LPS组较模型组死亡率下降,中性粒细胞浸润、P62和TNF-α均减少,而LC3-Ⅱ略升高;在3-MA-LPS组中,LC3-Ⅱ较LPS组降低,而中性粒细胞浸润、P62和TNF-α则没有差异。结果表明在LPS所致的脓毒症中,小鼠肺组织存在自噬流阻断,自噬体成熟障碍,RAP则能逆转LPS所致的肺组织自噬流障碍,改善细胞内环境,减轻炎性反应,降低死亡率。

This study was designed to examine the effects of autophagy on the lipopolysaccharide（LPS）-induced acute lung injury （ALI）and to analyze the possible mechanism.Kunming mice of clean grade were randomly divided into 6 groups：control group（saline;ip）;model group（LPS 10 mg/kg;ip）;RAP group（rapamycin 6 mg/kg;ip）;RAP＋LPS group （RAP 6 mg/kg and LPS 10 mg/kg;ip）;3-MA group （3-methyladenine 300 μg/kg;ip）;and 3-MA＋LPS group （3-MA 300 μg/kg and LPS 10 mg/kg;ip）.6 h after LPS injection;mortality was checked.Neutrophil aggregation;and the expressions of TNF-α;LC3 and P62 in lung tissue were checked by fluo-rescence microscopy and Western blot.The results revealed a higher mortality;neutrophil infiltration and TNF-αexpression and significantly increased levels of autophagy marker LC3-II and P62 in LPS group;in RAP＋LPS group;pretreatment with RAP notably reversed LPS-induced neutrophil infiltration and TNF-αexpression;LC3-II were further slightly increased;while P62 was significantly decreased;in 3-MA＋LPS group;pretreatment of 3-MA slightly decreased LC3-II expression;P62;neutrophil infiltration and TNF-αremained almost the same to those in LPS group.These data suggesed that;in sepsis;autophagy flux in the lung tissue is partially blocked;and RAP help to alleviate LPS-induced lung injury;which might through promoting autophagosome maturation;smoothing autophagy flux;and eventually to mitigate pulmonary inflammation.