Ma Yuanhang, Xu Chao, Wang Wensheng, Sun Ligang, Yang Songwei, Lu Dingsong, Liu Yong, Yang Hua
Department of General Surgery, Xinqiao Hospital, The Third Military Medical University, Chongqing 400037, China.
Zhonghua Wei Chang Wai Ke Za Zhi. 2014 Jun;17(6):602-6.
To observe the effect of SIRT1 on intestinal barrier function of epithelial Caco-2 cells under hypoxia and investigate its mechanism.
Caco-2 cells were randomly divided into three groups: normoxia group (Nx), hypoxia group (Hx,1%O2 for 6 h) and hypoxia plus 40 μmol/L Resveratrol (agonist of SIRT1) group (Hx+Res). Transepithelial electrical resistance (TER) was determined. mRNA and protein expressions of SIRT1 and tight junctions (ZO-1, Occludin, Claudin-1) were examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.
Both mRNA and protein expressions of SIRT1 were significantly reduced in Hx group as compared with Nx group (0.40±0.02 vs. 0.70±0.07, P=0.001; 0.37±0.03 vs. 0.76±0.03, P=0.001). The mRNA and protein expressions of SIRT1 were significantly increased in Hx+Res group as compared with Hx group(0.50±0.02 vs. 0.40±0.02, P=0.026; 0.54±0.02 vs. 0.37±0.03, P=0.011). The expression levels of ZO-1, Occludin and Claudin-1 in Hx group were lower than those in Nx group (P<0.05), however, pretreatment with Resveratrol could attenuate the decreased expression of above 3 molecules under hypoxia(P<0.05). TERs of Nx group, Hx group and Hx+Res group were (142±7) Ohm/cm(2), (94±3) Ohm/cm(2) and (119±7) Ohm/cm(2) respectively. Compare with the Nx group, the TER of Hx group was significantly decreased(P<0.05). TER of Hx+Res group was significantly increased compare with Hx group, but it was still significantly lower than that in Nx group(P<0.05).
Expression of SIRT1 is significantly reduced under hypoxia. Activation of SIRT1 can maintain the epithelial barrier function through regulating the expression of tight junctions under hypoxia.
观察沉默信息调节因子1（SIRT1）对缺氧状态下上皮Caco-2细胞肠屏障功能的影响并探讨其机制。
将Caco-2细胞随机分为三组：常氧组（Nx）、缺氧组（Hx，1%氧气处理6小时）和缺氧加40μmol/L白藜芦醇（SIRT1激动剂）组（Hx+Res）。测定跨上皮电阻（TER）。采用逆转录-聚合酶链反应（RT-PCR）和蛋白质免疫印迹法检测SIRT1及紧密连接蛋白（ZO-1、闭合蛋白、Claudin-1）的mRNA和蛋白表达。
与Nx组相比，Hx组SIRT1的mRNA和蛋白表达均显著降低（0.40±0.02对0.70±0.07，P=0.001；0.37±0.03对0.76±0.03，P=0.001）。与Hx组相比，Hx+Res组SIRT1的mRNA和蛋白表达显著增加（0.50±0.02对0.40±0.02，P=0.026；0.54±0.02对0.37±0.03，P=0.011）。Hx组ZO-1、闭合蛋白和Claudin-1的表达水平低于Nx组（P<0.05），然而，白藜芦醇预处理可减轻缺氧状态下上述3种分子表达的降低（P<0.05）。Nx组、Hx组和Hx+Res组的TER分别为（142±7）Ω/cm²、（94±3）Ω/cm²和（119±7）Ω/cm²。与Nx组相比，Hx组的TER显著降低（P<0.05）。与Hx组相比，Hx+Res组的TER显著升高，但仍显著低于Nx组（P<0.05）。
缺氧状态下SIRT1表达显著降低。激活SIRT1可通过调节缺氧状态下紧密连接蛋白的表达来维持上皮屏障功能。
