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

In this study, we hypothesized that different strains ofLactobacilluscan alleviate hyperlipidemia and liver steatosis via activation of 5 ' adenosine monophosphate-activated protein kinase (AMPK), 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 (n= 6) (i) normal diet (ND), (ii) HFD, (iii) HFD-statin (lovastatin 2 mg/kg/day), (iv) HFD-Lactobacillus fermentumDR9 (10 log CFU/day), (v) HFD-Lactobacillus plantarumDR7 (10 log CFU/day), and (vi) HFD-Lactobacillus reuteri8513d (10 log CFU/day). Rats administered with statin, DR9, and 8513d reduced serum total cholesterol levels after eight weeks (p< 0.05), while the administration of DR7 reduced serum triglycerides level after 12 weeks (p< 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 (p< 0.05); downregulation of hepatic lipid synthesis and beta-oxidation gene stearoyl-CoA desaturase 1 (SCD1), upregulation of hepatic sterol excretion genes of ATP-binding cassette subfamily G member 5 and 8 (ABCG5andABCG8), lesser degree of liver steatosis, and upregulation of hepatic energy metabolisms genesAMPK alpha 1andAMPK alpha 2. Taken altogether, this study illustrated that the administration of selectedLactobacillusstrains led to improved lipid profiles via activation of energy and lipid metabolisms, suggesting the potentials ofLactobacillusas a promising natural intervention for alleviation of cardiovascular and liver diseases.