Lactobacillus strains alleviated aging symptoms and aging-induced metabolic disorders in aged rats

Aging is an inevitable and ubiquitous progress that affects all living organisms. A total of 18 strains of lactic acid bacteria (LAB) were evaluated on the activation of adenosine monophosphate-activated protein kinase (AMPK), an intracellular energy sensor mediating lifespan extension. The cell-free supernatant (CFS) of Lactobacillus fermentum DR9 (LF-DR9), Lactobacillus paracasei OFS 0291 (LP-0291), and Lactobacillus helveticus OFS 1515 (LH-1515) showed the highest activation of AMPK and was further evaluated. The phosphorylation of AMPK by these three LAB strains was more evident in U2OS and C2C12 cells, compared to the other cell lines and control (P < .05). Using premature senescent Sprague-Dawley rats induced by D-galactose (D-gal), the administration of LAB (10 log CFU/rat/day) for 12 weeks prevented the shortening of telomere length in D-gal-treated rats compared to the untreated control (P < .05). LF-DR9 lowered gene expression of p53, a known senescent biomarker, in gastrocnemius muscle and tibia compared to the control. The selected LAB strains also enhanced lipid, renal, and liver profile of rats, suggesting added potential of the strains in preventing aging-induced metabolic diseases. Strain LP-0291 and LH-1515 showed ability to adhere to mucin, no antibiotic resistance, tolerated and proliferated under gastric and intestinal simulated conditions, and inhibited the growth of pathogens Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis, comparable to commercial probiotic LF-DR9 and Lactobacillus sakei Probio 65. This study provided an insight into the potential of LAB for exhibiting antisenescence effects, with potentials as new medicinal foods for targeted antiaging therapies.