Effects Of Sal B On The Antioxidant And Immune Function Of High Fat Diet Fed Mice

This investigation was conducted to evaluate the effect of high-fat diet on the oxidative stress, immune function and the coherent gene expression of mice. The experiment was also carried out to determine the effect of Salvianolic acid B (Sal B) on the scavenging of reactive oxygen species (ROS) and the regulating of immune system of high-fat diet fed mice. It provides a new theoretical basis for the regulation of immune dysfunction induced by high-fat diet.40 male C57BL/6 mice were randomly divided into 4 groups. The control group was fed with basal diet and the other three groups were respectively fed with high-fat diet, high-fat diet plus 0.002% Sal B and high-fat diet plus 0.004% Sal B. After 10 weeks, the plasma lipid status, ROS levels of blood and organs, the antioxidase activity and the content of MDA in plasma and organs were examined. The proportion of lymphocyte subsets in plasma and spleen, the apoptostic rates in spleen were determined respectively by FACSAria Flow Cytometer. In another experiment, 30 male C57BL/6 mice were randomly divided into 3 groups. The control group was fed with basal diet and the other two groups were respectively fed with high-fat diet, high-fat diet plus 0.002% Sal B. After 10 weeks, the levels of IL-6, TNF-α, IL-10,IFN-γand IL-4 in plasma were assayed by ELISA. In order to explore the molecular mechanisms underlying the modulating effect of Sal B on oxidative stress and immune dysfunction induced by high-fat diet, we examined the expression of Mt1, c-Jun, Vtn and Igh-6 in spleen by quantitative real-time reverse transcription–polymerase chain reaction.The results were as follows: (1) The levels of plasma lipid and ROS produced in blood and organs were significantly increased by feeding high-fat diet as compared with the controls. The anti-oxidative capacity of mice in high-fat diet groups was significantly decreased as compared with the controls. The supplement of Sal B could scavenge the excessive ROS, increase the anti-oxidative capacity of high-fat diet fed mice, and the effects were better at a low concentration (0.002%). (2) The supplement of 0.002% Sal B could regulate the ratio of lymphocyte subsets in peripheral blood and spleen of high-fat diet fed mice, it could also decrease the ratio of apotosis, the effects of low concentration (0.002%) were better than 0.004%. (3) The results showed that the contents of inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor-α(TNF-α) were relatively decreased, and anti-inflammatory cytokine interleukin-10 (IL-10) was increased with the supplement of 0.002% Sal B in high-fat diet fed mice. In the 0.002% Sal B group, the Th1 cytokine interferon-γ(IFN-γ) was relatively decreased, and the Th2 cytokine interleukin-4 (IL-4) was increased. The expression of c-Jun in spleen was significantly lowered and the expressions of Vtn, Igh-6 and Mt1 were significantly increased in high-fat diet fed mice with the supplement of 0.002% Sal B.High-fat diet resulted in oxidative stress and dysfunction in immune system. The optimum dose of Sal B (0.002%) could be able to eliminate the excessive ROS, increase the anti-oxidative capacity, regulate the immune dysfunction of high-fat diet fed mice.