Lactobacillus Strains Alleviated Hyperlipidemia and Liver Steatosis in Aging Rats via Activation of AMPK

Abstract

In this study, we hypothesized that different strains of <i>Lactobacillus</i> can alleviate hyperlipidemia and liver steatosis via activation of 5' adenosine monophosphate-activated protein kinase (<i>AMPK</i>), an enzyme that is involved in cellular energy homeostasis, in aged rats. Male rats were fed with a high-fat diet (HFD) and injected with D-galactose daily over 12 weeks to induce aging. Treatments included (<i>n</i> = 6) (i) normal diet (ND), (ii) HFD, (iii) HFD-statin (lovastatin 2 mg/kg/day), (iv) HFD-<i>Lactobacillus fermentum</i> DR9 (10 log CFU/day), (v) HFD-<i>Lactobacillus plantarum</i> DR7 (10 log CFU/day), and (vi) HFD-<i>Lactobacillus reuteri</i> 8513d (10 log CFU/day). Rats administered with statin, DR9, and 8513d reduced serum total cholesterol levels after eight weeks (<i>p</i> < 0.05), while the administration of DR7 reduced serum triglycerides level after 12 weeks (<i>p</i> < 0.05) as compared to the HFD control. A more prominent effect was observed from the administration of DR7, where positive effects were observed, ranging from hepatic gene expressions to liver histology as compared to the control (<i>p</i> < 0.05); downregulation of hepatic lipid synthesis and β-oxidation gene stearoyl-CoA desaturase 1 (<i>SCD1</i>), upregulation of hepatic sterol excretion genes of ATP-binding cassette subfamily G member 5 and 8 (<i>ABCG5</i> and <i>ABCG8</i>), lesser degree of liver steatosis, and upregulation of hepatic energy metabolisms genes <i>AMPKα1</i> and <i>AMPKα2</i>. Taken altogether, this study illustrated that the administration of selected <i>Lactobacillus</i> strains led to improved lipid profiles via activation of energy and lipid metabolisms, suggesting the potentials of <i>Lactobacillus</i> as a promising natural intervention for alleviation of cardiovascular and liver diseases.