Protective effects of two Lactobacillus plantarum strains in hyperlipidemic mice

To investigate the effects of Lactobacillus plantarum (L. plantarum) CAI6 and L. plantarum SC4 on hyperlipidemic mice.

Male Kunming mice were fed a high-cholesterol diet for 28 d to construct hyperlipidemic models. Hyperlipidemic mice and normal mice were assigned to 3 groups which were separately treated with L. plantarum CAI6, L. plantarum SC4, and physiological saline through oral gavage for 28 d. Total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels were measured by commercially available enzyme kits. FACS Calibur flow cytometry was used to examine hepatic and renal nuclear factor-erythroid 2-related factor 2 (Nrf2) expression. The morphology of livers was checked by hematoxylin and eosin staining and optical microscope observation.

Compared with normal mice, hyperlipidemic mice possessed significantly higher TC (3.50 ± 0.43 vs 2.89 ± 0.36, P < 0.01), TG (1.76 ± 0.07 vs 1.10 ± 0.16, P < 0.01), and LDL-C (1.72 ± 0.20 vs 0.82 ± 0.10, P< 0.01) levels, resulting in an increase of atherogenic index (AI) (2.34 ± 1.60 vs 0.93 ± 0.55, P < 0.05) and LDL-C/HDL-C ratio (1.43 ± 0.12 vs 0.51 ± 0.16, P < 0.05). After treatment with L. plantarum CAI6/L. plantarum SC4, TG (1.43 ± 0.27/1.54 ± 0.10 vs 1.76 ± 0.07, P < 0.01/P < 0.05) and LDL-C (1.42 ± 0.07/1.47 ± 0.12 vs 1.72 ± 0.20, P < 0.01/P < 0.01) in hyperlipidemic mice significantly decreased. In addition, TC, HDL-C, AI, and LDL-C/HDL-C ratio were all positively changed. Meanwhile, the treatment markedly alleviated hepatic steatosis and significantly stimulated Nrf2 expression (73.79 ± 0.80/72.96 ± 1.22 vs 54.94 ± 1.84, P < 0.01/P < 0.01) in hepatocytes of hyperlipidemic mice.

L. plantarum CAI6 and L. plantarum SC4 may protect against cardiovascular disease by lipid metabolism regulation and Nrf2-induced antioxidative defense in hyperlipidemic mice.