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
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摘要: 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，300 μg/kg)和3-MA-LPS组(3-MA 300 μg/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。Abstract: 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 fluorescence microscopy and Western blot. The results revealed a higher mortality, neutrophil infiltration and TNF-α expression 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-α expression, 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-α remained 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.
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Keywords:
- lipopolysaccharide /
- sepsis /
- autophagy /
- rapamycin /
- 3-methyladenine
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