自噬在大蒜素减轻脓毒症小鼠急性肺损伤中的作用

目的：探讨自噬在大蒜素减轻脓毒症小鼠急性肺损伤中的作用及机制。方法：将152只20~25 g的8周龄雄性Balb/c小鼠随机分为4组：假手术组(S组)、脓毒症组(CLP组)、大蒜素治疗组(Allicin组)及自噬抑制组(3-MA组)。脓毒症模型采用盲肠结扎穿孔法；Allicin组于术后6和12 h用大蒜素(30 mg/kg，腹膜内注射)干预；3-MA组在大蒜素干预之后0.5 h加用3-MA(15 mg/kg，腹膜内注射)；S组和CLP组于同时间点给予等量生理盐水。每组随机取20只小鼠，观察术后7 d生存率。每组各取12只小鼠，于术后24 h时收集肺泡灌洗液(bronchoalveolar lavage fl uid，BALF)(n=6)及肺组织(n=6)，采用ELISA法测定BALF中TNF-α和IL-6水平；HE染色观察肺部病理变化，免疫组织化学法测定肺组织自噬蛋白微管相关蛋白1轻链3B(microtubule-associated protein 1 light chain 3，LC3B)和Beclin-1的表达；采用比色法检测肺组织MDA含量及SOD活性。结果：与S组比较，CLP组7 d生存率降低(P<0.05)，BALF中TNF-α及IL-6水平升高(P<0.05)，肺损伤评分增加(P<0.05)，肺组织MDA含量增加、SOD活性下降(P<0.05)，肺组织LC3B及Beclin-1表达升高(P<0.05)；与CLP组比较，Allicin组7 d生存率升高(P<0.05)，BALF中TNF-α和IL-6水平降低(P<0.05)，肺损伤评分下降(P<0.05)，肺组织MDA含量下降，SOD活性增加(P<0.05)，肺组织LC3B和Beclin-1表达升高(P<0.05)；与Allicin组比较，3-MA组小鼠7 d生存率降低(P<0.05)，BALF中TNF-α和IL-6水平升高(P<0.05)，肺损伤评分增加(P<0.05)，肺组织MDA含量增加、SOD活性下降(P<0.05)，肺组织LC3B和Beclin-1表达降低(P<0.05)。结论：大蒜素可能通过增强自噬水平减轻脓毒症小鼠急性肺损伤。

Role of autophagy in ameliorating sepsis-induced acute lunginjury by allicinin in mice

Objective: To investigate roles of autophagy in ameliorating sepsis-induced acute lung injury byallicinin 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 mousemodel was established by cecal ligation and puncture (CLP). Mice in the allicin treatment groupwere given allicin (30 mg/kg, intra-peritoneal injection) at 6 and 12 h, while those in the autophagyinhibition group were given autophagy inhibitor 3-MA (15 mg/kg, intra-peritoneal injection) athalf an hour after allicin administration. Mice in the model and sham group were administered withthe same amount of saline. Twenty mice in each group were randomly chosen to observe the 7 dsurvival 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 showthe morphological changes in the lung tissues. Malondialdehyde (MDA) content and the activityof superoxide dismutase (SOD) in the lung tissues were examined. The expression of LC3B andBeclin-1 was determined by immunohistochemical analysis.Results: Compared with the sham group, the 7 d survival rate and lung SOD activity weredecreased in the CLP group (P<0.05); the lung morphological damage score, the levels of TNF-αand IL-6 in the BALF, MDA content in the lung, and expression of LC3B and Beclin-1 wereincreased 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 theallicin treatment group (P<0.05); the lung morphological damage scores, the levels of TNF-α andIL-6 in the BALF and MDA content in the lung were decreased obviously in the allicin treatmentgroup (P<0.05). Compared with the allicin treatment group, the 7 d survival rate, lung SODactivity, and the expressions of LC3B and Beclin-1 were decreased in the 3-MA group (P<0.05); thelung morphological damage scores, the levels of TNF-α and IL-6 in the BALF, and MDA content inthe 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 levelof autophagy.