Relationship between endogenous protection induced by autophagy against acute lung injury and inflammatory responses in septic mice / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the relationship between the endogenous protection induced by autophagy against acute lung injury and inflammatory responses in the septic mice.Methods A total of 130 pathogen-free male C57BL/6 mice,aged 6 weeks,weighing 20-25 g,were randomly divided into 5 groups (n =26 each) using a random number tablesham operation group (group S),sepsis group (group Sep),autophagy inducer rapamycin group (group Rap),autophagy inhibitor 3-methyladenine (3-MA) group (group 3-MA),and lysosome inhibitor bafilomycin group (group Baf).Sepsis was produced by cecal ligation and puncture in chloral hydrate-anesthetized mice.Rapamycin 10 mg/kg,3-MA 15 mg/kg,and bafilomycin 1 mg/kg were injected intraperitoneally at 1 h after operation in Rap,3-MA and Baf groups,respectively.Twenty mice in each group were selected and observed for the survival at 7 days after operation,and the 7-day survival rate was calculated.Six mice in each group were selected,and arterial blood samples were obtained at 24 h after operation,the mice were then sacrificed,and lung tissues were obtained for determination of the levels of tumor necrosis factor-alpha (TNF-α),high-mobility group box 1 (HMGB1),interleukin-6 (IL-6),IL-10 and monocyte chemotactic protein-1 (MCP-1) in serum and lung tissues by enzyme-linked immunosorbent assay.The expression of autophagy-related proteins microtubule-associated protein 1 light chain 3 Ⅱ (LC3 Ⅱ),Beclin-1 and lysosomal-associated membrane protein 2 (LAMP2),and Ras-related protein 7 (Rab7) in lung tissues was detected by Western blot.Results Compared with group S,the 7-day survival rate was significantly decreased,and the levels of TNF-α,HMGB1,IL-6,IL-10 and MCP-1 in serum and lung tissues and LC3 Ⅱ,Beclin-1,LAMP2 and Rab7 in lung tissues were significantly increased in group Sep (P＜0.05).Compared with group Sep,the 7-day survival rate and levels of IL-10,LAMP2 and Rab7 in serum and lung tissues were significantly increased in group Rap and decreased in 3-MA and Baf groups,and the levels of TNF-α,HMGB1,IL-6 and MCP1 in serum and lung tissues were significantly decreased in group Rap and increased in 3-MA and Baf groups,and the levels of LC3 Ⅱ and Beclin-1 in lung tissues were significantly increased in Rap and Baf groups and decreased in group 3-MA (P＜0.05).Conclusion Autophagy-induced endogenous protection against acute lung injury is related to inhibition of inflammatory responses in the septic mice.