细胞型Fas相关死亡区域蛋白样白介素-1β转换酶抑制蛋白（cFLIP）, 重症急性胰腺炎, 肺损伤, 中性粒细胞, 细胞凋亡, 大鼠

Objective To explore the role and possible mechanism of silencing cellular FLICE-like inhibitory protein (cFLIP) in severe acute pancreatitis (SAP) induced lung injury. Methods Twelve SD rats were randomly divided into the control group, cFLIPL (cFLIPS) siRNA1 group, cFLIPL (cFLIPS) siRNA2 group, and cFLIPL (cFLIPS) siRNA3 group. The cFLIPL siRNA and cFLIPS siRNA with the highest inhibition rate were screened. Fifty SD rats were randomly divided into the sham surgery group, model control group, cFLIP siRNA-NC group, cFLIPS siRNA group, and cFLIPL siRNA group. A SAP model was established by retrograde injection of 3%

sodium taurocholate solution into the pancreatic bile duct. After successful modeling, rats in the cFLIPS siRNA group, cFLIPL siRNA group, and cFLIP siRNA-NC group were injected with corresponding siRNA solution via the tail vein, while the remaining 2 groups were injected with an equal amount of 0.9% NaCl. HE staining was used to detect pathological changes in lung tissue; ELISA was used to detect the content of IL-6, IL-1β and TNF-α; The fully automatic analyzer was used to detect the number of white blood cells and neutrophils in venous blood; Neutrophil apoptosis was detected by flow cytometry; The expression of neutrophil RIP1 and

caspase-8 proteins were detected by Western blotting. Results The cFLIPL siRNA2 group and cFLIPS siRNA1 group showed the most significant interference efficiency, so these 2 groups were selected for subsequent experiments. Compared with the model control group rats, the cFLIPL siRNA group and cFLIPS siRNA group rats showed reduced alveolar structural damage, thinning of alveolar walls, and reduced infiltration of inflammatory cells. Compared with the model control group, the cFLIPL siRNA group and cFLIPS siRNA group showed that the contents of IL-6, IL-1β and TNF-α were significantly decreased, the numbers of white blood cells and neutrophils in venous blood were significantly decreased, the apoptosis rates of neutrophils were significantly increased, the expression levels of cFLIPL, cFLIPS, and RIP1 protein were significantly decreased, and the expression level of caspase-8 protein was significantly increased; the above differences were all statistically significant (P<0.05). Conclusion This experimental study suggests that, targeted silencing of cFLIP may promote neutrophil apoptosis by upregulating the expression of caspase-8 and inhibiting the expression of RIP1, and may reduce the release of inflammatory mediators IL-6, IL-1β and TNF-α, inhibit the neutrophil infiltration in lung tissue, and then alleviate the lung damage induced by SAP.

cellular FLICE-like inhibitory protein, severe acute pancreatitis, lung injury, neutrophils, cellapoptosis, rats