乳酸乳球菌对Caco-2细胞抗氧化功能的影响

Effect of Lactococcus lactis on Antioxidant Functions of Caco-2 Cells under Oxidative Stress

本文旨在研究乳酸乳球菌对氧化应激状态下Caco-2细胞抗氧化功能的影响。将培养好的Caco-2细胞分为3组:空白对照组和氧化应激组分别加入终浓度为0和100μmol/L H_2O_2,处理组在H_2O_2氧化应激条件下同时添加乳酸乳球菌(1×108CFU/m L)。培养至12 h和48 h时分别测定培养上清和细胞裂解液中的抗氧化指标。结果表明:与空白对照组相比,氧化应激12 h并没有对细胞造成明显的损伤;48 h时细胞发生了严重的氧化应激,培养上清中T-AOC(P<0.05)、抗O_2-(P<0.01)、GSH-Px(P<0.01)和CAT(P<0.05)活力均显著降低,MDA含量极显著增加(P<0.01)。与氧化应激组相比,乳酸乳球菌处理12 h时显著提高了细胞培养上清中T-AOC、SOD、CAT活力(P<0.01)和GSH含量(P<0.01)以及细胞裂解液中SOD活力(P<0.01)和GSH含量(P<0.05);处理48 h时显著提高了上清中抗O_2^-、SOD、GSH-Px、CAT活力(P<0.01),显著抑制了H_2O_2诱导的胞内SOD活性、GSH含量的升高和POD活性的降低(P<0.01),虽然T-AOC无显著变化(P>0.05),但培养上清中MDA含量显著减少(P<0.01)。以上结果表明,在体外条件下,乳酸乳球菌可通过提高不同抗氧化酶活力,改善胞内抗氧化防御系统,增强Caco-2细胞抗氧化功能,减轻细胞的氧化应激损伤。

The present study was designed to investigate the effects of Lactococcus lactis on a ntioxidant functions of Caco-2 cells under oxidative stress. Caco-2 cells were cultured and randomly divided into three groups： the control group and oxidative stress group were respectively exposed to 0 or 100 μmol/L hydrogen peroxide; the treatment group was treated with Lactococcus lactis （1 × 10^8 CFU/mL） under the condition of oxidative stress. Antioxidative indicators of cell supernatant and lysate were measured after incubation for 12 h and 48 h. The results showed that, no significant damage was found in cells under oxidative stress for 12 h compared with control group, while cells suffered severe oxidative stress after 48 h, which accompanied with remarkable drop of total antioxidant capacity （T-AOC） （P〈0.05）, anti-superoxide anion radical （anti-O2^-） （P〈0.01）, glntathione peroxidase （GSH-Px） （P〈0.01） as well as catalase （CAT） （P〈0.05） activities, and an increase of malondialdehyde （MDA） content （P〈0.01） in the culture supernatant. Compared with oxidative stress group, cells treated with Lactococcus lactis for 12 h manifested significant increases of T-AOC, superoxidase （SOD）, CAT activities and glutathione （GSH） content in cultural supematant （P〈0.01）, and higher superoxidase （SOD） activity （P〈0.01）, GSH content （P〈0.05） in cell lysate; cells treated for 48 h was observed a remarkable increase levels of anti-O2^-, SOD, GSH-Px, CAT activities （P〈0.01） in cell supernatant and distinct alleviation of increases in SOD activities and GSH content, as well as reduction in peroxidase （POD） which induced by hydrogen peroxide （P〈0.01） in cell lysate. Additionally, MDA content （P〈0.01） was significantly decreased, although there was no significant change in T-AOC （P〉0.05） in cell supernatant. The current findings indicated that Lactococcus lactis could increase the antioxidant functions of Caco-2 cells under oxidative stress in vitro by enhancing different antioxidant enzymatis activities and improving antioxidant defense systems in cells, thus alleviating oxidative stress damage.