[Endoplasmic reticulum stress regulates autophagy and tumor necrosis factor-α secretion of RAW264.7 cells induced by silica].

Objective: To investigate the role of endoplasmic reticulum stress (ERS) in the autophagy of RAW264.7 cells induced by SiO(2) and its effect on the secretion of tumor necrosis factor-α. Methods: RAW264.7 cells stimulated by 200 μg/ml SiO(2) were used as an vitro cell model, and different treatment times of SiO(2) were used as variables. They were divided into 0 h treatment group (blank control group) , 6 h, 12 h, 24 h, and 48 h treatment group. The formation of autophagospores was detected by acridine orange and mondane-sulfonate (MDC) staining. Application of real-time quantitative PCR (Real-time PCR) to detect autophagy related molecular Beclin1 mRNA expression and protein immunoblot (Western Blotting) detecting autophagy related proteins LC3Ⅰ, LC3Ⅱ and expression of Beclin1. Real-time PCR and Western blotting were used to detect the expression of ERS specific marker BiP. Secretion of RAW 264.7 cell transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) was detected by enzyme-linked immunosorbent assay (ELISA) . ERS inhibitors 4-PBA intervention experiment, including blank control group, SiO(2), 1 μmol/L 4-PBA+SiO(2), 10 μmol/L 4-PBA+SiO(2), 20 μmol/L 4-PBA+SiO(2) treatment group, Western blotting testing LC3Ⅰ, LC3Ⅱ and expression of Beclin1 changes. Results: Compared with the control group, SiO(2)-induced fluorescence intensity in RAW264.7 cells was significantly increased, with statistically significant differences (P<0.05) . Compared with control group, with SiO(2) processing time prolonged, LC3Ⅰ, LC3Ⅱ Beclin1 mRNA and protein expression and protein expression increased, 6 h, 24 h, the height of the differences were statistically significant (P<0.05) ; Compared with the control group, the mRNA and protein expression level of BiP reached the peak for 6 h, and the expression level in 6 h, 12 h and 24 h groups increased significantly, and the difference was statistically significant (P<0.05) . Compared with the SiO(2) stimulation group, the LC3Ⅱand Beclin 1 protein levels of RAW264.7 cells were gradually down-regulated by increasing the dose of 4-PBA. With the increase of 4-PBA concentration, the down-regulated levels were more significant, and the difference was statistically significant (P<0.05) . Compared with the SiO(2) stimulation group, the TNF-α secretion level of RAW264.7 cells significantly decreased of 1, 10, 20 μmol/L 4-PBA+SiO(2) treatment group, and the difference was statistically significant (P<0.05) . Conclusion: ERS induced by SiO(2) is involved in the secretion of autophagy and TNF-α in RAW264.7 cells.目的： 探讨内质网应激（ERS）在二氧化硅（SiO(2)）诱导的RAW264.7细胞自噬中的作用及对肿瘤坏死因子-α（TNF-α）分泌的影响。 方法： 以200 μg/ml SiO(2)刺激的RAW264.7细胞为体外细胞模型，以SiO(2)不同处理时间分组，包括0 h组（对照组）、6、12、24和48 h组，通过吖啶橙及单丹（磺）酰戊二胺荧光（MDC）染色检测细胞自噬小体的形成。应用实时聚合酶链反应（实时PCR）检测自噬相关分子Beclin1 mRNA表达，蛋白免疫印迹（western blotting）检测自噬相关蛋白LC3Ⅰ、LC3Ⅱ与Beclin1的表达；应用实时PCR和western blotting检测ERS特异标记分子BiP的表达；酶联免疫吸附法（ELISA）检测RAW 264.7细胞转化生长因子-β1（TGF-β1）和TNF-α的分泌。以ERS抑制剂4-PBA进行干预试验，包括空白对照组、SiO(2)组、1 μmol/L 4-PBA+SiO(2)组、10 μmol/L 4-PBA+SiO(2)组、20 μmol/L 4-PBA+SiO(2)组，检测各组LC3Ⅰ、LC3Ⅱ与Beclin1蛋白的表达及TGF-β1、TNF-α的分泌变化。 结果： 与对照组比较，SiO(2)诱导RAW264.7细胞各时间组荧光强度均明显增强，差异均有统计学意义（P<0.05）；与对照组比较，SiO(2)诱导RAW264.7细胞各时间组的Beclin1 mRNA表达均明显增加，LC3Ⅰ、LC3Ⅱ和Beclin1蛋白表达均明显增加，差异均有统计学意义（P<0.05）；与对照组比较，SiO(2)诱导RAW264.7细胞6、12、24 h组BiP mRNA和蛋白表达均明显增加，6 h达高峰，差异均有统计学意义（P<0.05）；与SiO(2)组比较，随着4-PBA浓度增加，RAW264.7细胞的LC3-II和Beclin 1蛋白水平逐渐下调，差异均有统计学意义（P<0.05）；与SiO(2)组比较，1、10、20 μmol/L 4-PBA+SiO(2)组RAW264.7细胞TNF-α分泌水平明显下降，差异均有统计学意义（P<0.05）。 结论： SiO(2)诱导的ERS可能参与了RAW264.7细胞自噬以及TNF-α的分泌过程。.