抗氧化活性酸奶对D-半乳糖诱导氧化损伤大鼠脑的保护作用

研究植物乳杆菌(Lactobacillus plantarum)NDC75017和嗜热链球菌(Streptococcus thermophilus)偶联发酵酸奶对D-半乳糖(D-galactose,D-Gal)氧化损伤大鼠大脑的保护作用。实验分为6个组,包括空白对照组、阴性对照组(D-Gal模型)、阳性对照组(VE)、酸奶低、中、高剂量组。检测大鼠的超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、谷胱甘肽过氧化物酶(glutathione peroxidase,GSH-Px)、诱导型一氧化氮合酶(inducible nitric oxide synthase,i NOS)活力,丙二醛(malondialdehyde,MDA)、一氧化氮含量以及大鼠体质量变化,脑组织中半胱氨酸天冬氨酸蛋白酶(caspase)-3、caspase-9的表达,并采用苏木素伊红(hematoxylin and eosin,HE)染色分析脑损伤程度。结果表明,与阴性对照相比,酸奶各剂量组能增强大鼠脑组织SOD、GSH-Px、CAT活力,同时降低MDA、NO的含量和i NOS活力。其中,高剂量处理组对提高脑组织SOD、GSH-Px活力效果最好,分别比阴性对照组提高了67.8%、22.8%(P0.05)。高剂量酸奶组使大脑CAT活力达到了阳性对照组的水平(P0.05)。在大鼠脑中,随着酸奶剂量的升高,MDA含量也随之下降,其中高剂量效果最好,达到了空白对照水平(P0.05)。同时,酸奶各剂量组对降低NO的含量和i NOS活力也有一定的效果。结论:植物乳杆菌和嗜热链球菌偶联发酵酸奶能够通过提高衰老大鼠血清和脑组织内抗氧化酶系的活力,降低MDA、NO的含量和i NOS活力,并抑制了caspase-9、caspase-3的表达。HE染色结果也证实,一定量的酸奶能减少氧化应激对脑组织的损害,具有延缓衰老的作用。

Protective Effect of Antioxidant Yogurt against D-Galactose-Induced Brain Damage in Rats

The aim of this study was to evaluate the protective effect of yogurt fermented by a mixed culture of Lactobacillus plantarum NDC75017 and Streptococcus thermophilus on D-galactose (D-Gal)-induced brain damage in rats. Wistar rats were divided into six groups, including normal control, negative control, low-, medium- and high-dose yogurt, and D-Gal + VE (positive control) groups. The activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and inducible nitric oxide synthase (iNOS), and malondialdehyde (MDA) and nitric oxide (NO) concentrations in rat serum and brain tissue, body weight, and the expression of caspase-3 and caspase-9 in rat brain were tested. Histopathological examination with hematoxylin and eosin (HE) staining was used to analyze the extent of brain damage. The results showed that compared with the negative control group, all doses of the yogurt enhanced SOD, GSH-Px and CAT activities, and decreased MDA and NO concentrations as well as iNOS activity in rat brain. The yogurt at high dose was the most effective in enhancing SOD and GSH-Px activities, resulting in an increase of 67.8% and 22.8% compared with the negative control group, respectively (P < 0.05). Moreover, brain CAT activity in the high-dose yoghurt group was comparable to that in the positive control group (P > 0.05). In rat brain, MDA level declined with increasing dose (P > 0.05), closest to that of the normal control group at high dose. At the same time, all doses of the yogurt also reduced NO level and iNOS activity. Conclusion: Yogurt co-fermented by Lactobacillus plantarum and Streptococcus thermophilus can protect the rat brain against D-Gal-induced oxidative damage by improving antioxidant enzymes activities in serum and brain tissue, reducing MDA and NO concentrations and iNOS activity, and decreasing the expression of caspase-9 and caspase-3, which was also confirmed by HE staining results.