Reduction in serum lipid parameters by incorporation of a native strain of Lactobacillus Plantarum A7 in Mice

Abstract

Background: Probiotics has recently been considered as an alternative biological method for chemical agents in reduction of plasma cholesterol. However, the results of human and animal studies showed various results and sometimes strain dependency and host specify of probiotic strains have explained as the possible reasons for such variations. Therefore, it seems necessary to find new probiotic agents among the native strains through in-vivo experiments.
Methods: Lactobacillus bacteria isolated from fecal samples of infants and Lactobacillus plantarum A7 was selected due to its potent resistance to biliary secretions for evaluation of its effects on cholesterol reduction in mice. Sixteen male rats were fed with a high cholesterol regimen for 14 days (pre-intervention period), and their serum blood samples analyzed for cholesterol, triglyceride, LDL and HDL. Then they randomly divided into two groups (control and treated groups). Treated group received 10⁸ CFU/ml of Lactobacillus plantarum A7 with the diet formulation which was used in pre-intervention period for 14 days; while, the control group continued to receive the same formula and did not receive any bacteria (intervention period). Serum samples were analyzed for lipid parameters. Blood, spleen and liver samples of both groups were evaluated for translocation.    
Results: In pre-intervention period, mean values of cholesterol, triglyceride, HDL and LDL in treated group were 101.3, 105.1, 40.9 and 35.6 mg/dl, respectively and no significance difference was observed between treated and control groups. During intervention period, the mean values of cholesterol, triglyceride, HDL and LDL in treated group were 92, 97.7, 46 and 30.4 mg/dl, respectively and total cholesterol, triglyceride and LDL reduced significantly in treated group but for HDL this difference was not significant. All the translocation tests were negative for either the strain tested.
Conclusion: L. plantarum A7 is effective in lowering serum lipid levels in rats. Furthermore, daily usage of 10⁸ cells of this strain could be considered safe, regarding its translocation from intestinal lumen to other organs, although more studies on safety must be done in the future.

Keywords: Probiotics, Lactobacillus plantarum, Cholesterol