自噬相关蛋白LC-3和Beclin-1在大鼠硅沉着病发生中的表达及意义

目的 观察自噬相关蛋白LC-3和Beclin-1在大鼠硅沉着病模型中的表达及意义，并探讨其机制；从细胞自噬角度研究硅沉着病形成的分
子机制。方法 将90只健康SD雄性大鼠随机分为对照组、模型组和自噬抑制剂3-甲基腺嘌呤（3-MA）组，每组30只。采用非暴露式气管插管一次
性灌注二氧化硅粉尘混悬液法建立大鼠硅沉着病模型，并给予3-MA干预，各组分别于造模后第1、3、7、14及28 天分批处死6只大鼠。留取肺组织，
HE和Masson染色观察肺组织形态变化； 免疫组织化学染色检测LC-3、Beclin-1的表达及分布；免疫印迹法检测LC-3、Beclin-1的蛋白表达量。结果
与对照组相比，模型组有显著的肺泡炎改变、明显的矽结节形成及大量胶原沉积。LC-3、Beclin-1在各时间点的表达均上调（P＜0.05），并随
时间呈现动态变化趋势，SiO2 注入后1 d表达有升高趋势，14d达高峰（P＜0.05），28 d回落，但仍高于基础表达。与模型组相比，3-MA组肺泡
炎减轻，矽结节减小，胶原沉积减少，LC-3、Beclin-1在各时间点的表达均下调（P＜0.05），各时间点的变化趋势无显著性改变。结论 细胞自
噬参与大鼠硅沉着病的病理进程，并在硅沉着病的发生与发展过程中起重要作用。

Expression and significance of autophagy related proteins LC-3 and Beclin-1 in silicosis occurrence in rats

Objective To investigate the expression of autophagy-related proteins LC-3 and Beclin-1 in the rat silicosis model
and its mechanisms, and to study the molecular mechanism of silicosis formation from cells autophagy perspective. Methods Ninety
healthy male SD rats were randomly divided into three groups: control group, model group and autophagy inhibitor 3-methyladenine
(3-MA) group (n=30). The rat silicosis model was made by one-time infusion of the silica dust suspension method, using the
non-exposed tracheal intubation, and was given the 3-MA. The rats were sacrificed on the 1st, 3rd, 7th, 14th and 28th day after
the modeling. The morphological changes of lung tissue were observed by HE and Masson staining.The expression of LC-3 and Beclin-1
were detected by means of immunohistochemistry and Western blotting. Results There were alveolitis change, silicosis nodules
formation and collagen deposition in the model group.The intensities of immunohistochemical positive reaction for LC-3 and Beclin-1
increased at all time points in the model group (P<0.05). LC-3 and Beclin-1 expressions began to increase at the 1st day, peaked
at the 14th day(P＜0.05), and decreased at the 28th day, but higher than basal expression. Compared with the model group, alveolitis
change, the area and number of silicotic nodules and collagen deposition decreased, and the expression of LC-3 and Beclin-1
decreased at all time points in the 3-MA group(P＜0.05). No significant changes in the trend of each point in time was observed.
Conclusion Autophagy may be involved in the pathological process of silicosis in rats, and played an important role in the
occurrence and development of silicosis.