目的:探讨沉默信息调节因子1(SIRT1)激活剂SRT1720对大鼠体外循环肺损伤的保护作用及其机制。方法:选取60只远交群SD大鼠，按照随机数字表法分为对照组、模型组和SRT1720组，对照组大鼠行动静脉穿刺置管术，模型组和SRT1720组大鼠行体外循环转流2 h。对照组和模型组泵注与SRT1720组相同体积的生理盐水，SRT1720组大鼠在体外循环前给予SRT1720 2 mg/kg。观察3组大鼠氧合指数和呼吸指数；苏木精-伊红(HE)染色观察3组大鼠肺部病理性改变；采用酶联免疫吸附试验(ELISA)分析血清肿瘤坏死因子-α(TNF-α)、白细胞介素(IL)-6和IL-10炎性因子的水平；采用酶促反应检测血清丙二醛(MDA)和超氧化物歧化酶(SOD)水平；采用蛋白质印迹法(Western blot)分析3组内质网应激相关蛋白葡萄糖调节蛋白78(GRP78)、C/EBP同源蛋白(CHOP)、半胱氨酰天冬氨酸特异性蛋白酶(Caspase)-12表达水平。计量资料比较采用单因素方差分析。结果:SRT1720组大鼠呼吸指数(1.97±0.04)低于模型组大鼠呼吸指数(2.63±0.03)，而氧合指数(340.48±20.48)高于模型组大鼠氧合指数(208.39±16.79)，差异有统计学意义(n t＝4.196，n P<0.05；n t＝2.519，n P<0.05)。SRT1720组大鼠肺组织病理评分(4.69±0.31)低于模型组大鼠病理评分(8.46±0.47)，差异有统计学意义(n t＝2.849，n P<0.05)。SRT1720组大鼠外周血清IL-6水平[(128.64±8.27) ng/L]低于模型组大鼠外周血清IL-6[(198.25±10.89) ng/L]，而SRT1720组大鼠外周血清IL-10水平[(68.51±6.91) ng/L]高于模型组大鼠外周血清IL-10水平[(30.28±3.19) ng/L]，差异均有统计学意义(n t＝2.184，n P<0.05；n t＝2.011，n P<0.05)。SRT1720组大鼠外周血清MDA水平[(9.88±1.11) μmol/L]低于模型组大鼠外周血清MDA水平[(15.33±2.87) μmol/L，而SOD水平[(147.32±8.90) U/ml]高于模型组大鼠外周血清SOD水平[(98.69±8.99) U/ml]，差异均有统计学意义(n t＝3.408，n P<0.05；n t＝3.001，n P<0.05)。SRT1720组大鼠肺组织GRP78、CHOP和Caspase-12蛋白相对水平[(0.62±0.12)、(0.39±0.10)、(0.87±0.11)]低于模型组大鼠肺组织GRP78、CHOP和Caspase-12蛋白相对水平[(1.12±0.10)、(0.69±0.09)、(1.54±0.13)]，差异均有统计学意义(n t＝4.150，n P<0.05；n t＝2.988，n P<0.05；n t＝3.405，n P<0.05)。n 结论:SIRT1激活剂SRT1720可显著下调体外循环引起的炎性反应，清除自由基和降低细胞内质网应激，进而缓解肺组织损伤。“,”Objective:To investigate the protective mechanism of silent information regulator 1 (SIRT1) activator SRT1720 on lung injury induced by cardiopulmonary bypass (CPB).Methods:A total of 60 SD rats from June 2018 to June 2019 were randomly divided into control group, model group and SRT1720 group by random number table. The rats in the control group underwent venipuncture and catheterization, and those in the model group and SRT1720 group underwent cardiopulmonary bypass for 2 h. Rats in the control group and model group were injected with the same volume of normal saline as SRT1720 group. Rats in SRT1720 group were given SRT1720 (2 mg/kg) during cardiopulmonary bypass. The levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6 and IL-10 inflammatory factors in serum were analyzed by enzyme linked immunosorbent assay (ELISA). The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in serum were measured by enzymatic reaction. The expression levels of glucose regulated protein 78 (GRP78), C/EBP homologous protein (CHOP) and Caspase-12 were detected by Western blotting. One-way analysis of variance (ANOVA) was used to compare the data between groups, andn P<0.05 was considered to be statistically significant.n Results:Compared with the model group [the respiratory index and oxygenation index at 4 h after cardiopulmonary bypass (2.63±0.03, 208.39±16.79)], the respiratory index in SRT1720 group (1.97±0.04) significantly decreased, and the oxygenation index (340.48±20.48) significantly increased (n t=4.196, n P<0.05;n t=2.519, n P<0.05). Compared with the pathological score of model group (8.46±0.47), the pathological score of lung tissue in SRT1720 group significantly decreased (4.69±0.31,n t=2.849, n P<0.05). Compared with the level of IL-6 and IL-10 in the model group [(198.25±10.89), (30.28±3.19) ng/L], the level of IL-6 [(128.64±8.27) ng/L] in SRT1720 group significantly decreased, and the level of IL-10 [(68.51±6.91) ng/L] significantly increased (n t=2.184, n P<0.05;n t=2.011, n P<0.05). Compared with the level of malondialdehyde (MDA) and superoxide dismutase (SOD) in the model group [(15.33±2.87) μmol/L, (98.69±8.99) U/ml], the level of MDA in SRT1720 group [(9.88±1.11) μmol/L] significantly reduced (n t=3.408, n P<0.05), and the level of SOD in SRT1720 group [(147.32±8.90) U/ml] significantly increased (n t=3.001, n P<0.05). Compared with the relative protein levels of GRP78, CHOP and Caspase-12 in lung tissue of rats in model group (1.12±0.10, 0.69±0.09, 1.54±0.13), the relative protein levels of glucose-regulated protein78 (GRP78), C/EBP-homologous protein (CHOP) and cysteinyl aspartate specific proteinase (Caspase)-12 protein in lung tissue of rats in SRT1720 group (0.62±0.12, 0.39±0.10, 0.39±0.10, 0.87±0.11) significantly reduced (n t=4.150, n P<0.05;n t=2.988, n P<0.05;n t=3.405, n P<0.05).n Conclusion:SIRT1 activator SRT1720 can significantly alleviate lung injury in cardiopulmonary bypass by down-regulating the inflammatory response induced, eliminating free radicals and reducing endoplasmic reticulum stress.