[Role of autophagy in ameliorating sepsis-induced acute lung injury by allicinin in mice].

OBJECTIVE: To investigate roles of autophagy in ameliorating sepsis-induced acute lung injury by allicinin in mice.
 Methods: A total of 152 male Balb/c mice (8-week old) were randomly divided into a sham group, a septic model group, an allicin treatment group, and an autophagy inhibition group. Septic mouse model was established by cecal ligation and puncture (CLP). Mice in the allicin treatment group were given allicin (30 mg/kg, intra-peritoneal injection) at 6 and 12 h, while those in the autophagy inhibition group were given autophagy inhibitor 3-MA (15 mg/kg, intra-peritoneal injection) at half an hour after allicin administration. Mice in the model and sham group were administered with the same amount of saline. Twenty mice in each group were randomly chosen to observe the 7 d survival rate. The other 12 mice were killed at 24 h, and the bronchoalveolar lavage fluid (BALF) (n=6) and lung tissues (n=6) were collected. ELISA was used to detect the tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the BALF. Hematoxylin-eosin staining was preformed to show the morphological changes in the lung tissues. Malondialdehyde (MDA) content and the activity of superoxide dismutase (SOD) in the lung tissues were examined. The expression of LC3B and Beclin-1 was determined by immunohistochemical analysis.
 Results: Compared with the sham group, the 7 d survival rate and lung SOD activity were decreased in the CLP group (P<0.05); the lung morphological damage score, the levels of TNF-α and IL-6 in the BALF, MDA content in the lung, and expression of LC3B and Beclin-1 were increased greatly in the CLP group (P<0.05). Compared with the CLP group, the 7 d survival rate, lung SOD activity and the expressions of LC3B and Beclin-1 were increased significantly in the allicin treatment group (P<0.05); the lung morphological damage scores, the levels of TNF-α and IL-6 in the BALF and MDA content in the lung were decreased obviously in the allicin treatment group (P<0.05). Compared with the allicin treatment group, the 7 d survival rate, lung SOD activity, and the expressions of LC3B and Beclin-1 were decreased in the 3-MA group (P<0.05); the lung morphological damage scores, the levels of TNF-α and IL-6 in the BALF, and MDA content in the lung were increased significantly in the 3-MA group (P<0.05).
 Conclusion: Allicin may ameliorate sepsis-induced acute lung injury in mice by enhancing the level of autophagy.