SIRT1在TNF-α介导的肠上皮屏障破坏中的作用及机制研究

Action machanism of SIRT1 involves TNF-α-induced intestinal epithelial barrier destroy

目的观察沉默信息调节因子1(SIRT1)对肿瘤坏死因子-α(TNF-α)介导的肠上皮Caco-2细胞屏障功能破坏的影响并探讨其分子机制。方法将Caco-2细胞分3组处理:对照组、TNF-α100ng/mL 24h处理组(TNF-α组)及TNF-α100ng/mL24h处理+白芦藜醇(Resveratrol)40μm预处理12h组(TNF-α+Res组)。分别检测跨上皮电阻(TER)、SIRT1及紧密连接蛋白:ZO-1、occludin的蛋白表达。结果对照组、TNF-α组、TNF-α+Res组的SIRT1蛋白相对表达量分别为0.81±0.02、0.43±0.04、0.60±0.03。3组的TER分别为(154.00±5.00)、(97.00±4.00)、(128.00±6.00)Ohm/cm2。TNF-α组SIRT1的蛋白表达较对照组下降47.00%,TER降低37.00%,经白芦藜醇预处理使TER较TNF-α组升高32.00%。对照组、TNF-α组、TNF-α+Res组的ZO-1和occludin蛋白相对表达量分别为0.62±0.06和0.57±0.03、0.23±0.05和0.33±0.04、0.41±0.03和0.50±0.02。TNF-α处理后紧密连接蛋白ZO-1、occludin表达显著降低(P<0.05),而白芦藜醇预处理可缓解该现象,蛋白表达较TNF-α组分别升高78.00%、51.00%(P<0.05)。结论 TNF-α处理条件下SIRT1水平降低,而升高SIRT1水平可增加肠道紧密连接蛋白ZO-1、occludin蛋白水平的表达,从而减轻TNF-α对Caco-2细胞构成的上皮屏障功能的损伤。

Objective To observe the influence of silent information regulator factor 1（SIRT1）on TNF-αinduced intestinal epi-thelial Caco-2 cell barrier function destroy and to investigate its molecular machenism.Methods Caco-2 cells were randomly divided into three groups：normal control group （control）,TNF-αgroup （TNF-α,100 ng/mL for 24 h）and 100 ng/mL plus 40μm resvera-trol group （TNF-α＋Res）.Transepithelial electrical resistance （TER）was determined.SIRT1 and the protein expressions of ZO-1 , occludin were examined by using Western blot.Results The relative expression amounts of SIRT1 protein were 0.81 ± 0.02, 0.43±0.04 and 0.60±0.03 respectively.TER of three groups were （154.00±5.00）,（97.00±4.00）and（128.00±6.00）Ohm/cm2 respectively.Compared with the control group,the expression of SIRT1 protein was reduced by 47% and TER was decreased by 37.00% in the TNF-αgroup.After resveratrol precondition,TER was increased by 32.00% compared with the TNF-αgroup. The relative expression amounts of ZO-1 and occludin protein in the control group,TNF-αgroup and TNF-α＋Res group were （0.62±0.06,0.57±0.03）,（0.23±0.05,0.33±0.04）and（0.41±0.03,0.50±0.02）respectively.After TNF-αtreatment,the ex-pressions of ZO-1 and occludin protein were significantly deceased（P〈0.05）,but the resveratrol precondition could attenuate this phenomenon,compared with TNF-αgroup,the protein expression was increased by 78.00% and 51.00% respectively （P〈0.05）. Conclusion Under the condition of TNF-αtreatment,the SIRT1 level is decreased,but increasing SIRT1 level could increase the in-testinal tight j unction protein ZO-1 and occludin protein expression,thus alleviate the damage of TNF-αon the epithelial barrier function constituted by Caco-2 cells.