Effects of Lacticaseibacillus rhamnosus LB1.5 as potential probiotic supplement on the liver and adipose tissue of adult male mice to a high-fat diet.

This study aimed to investigate the effects of Lacticaseibacillus rhamnosus LB1.5 supplementation on liver and adipose tissue morphology, oxidative stress, and the relative gene expression of Sirt1, Gpx1, and Il6 in the liver of HFD-fed mice. Male C57BL/6 mice received: (i) a control diet (CONT), (ii) a control diet with probiotics (Lact. rhamnosus LB1.5, 1.3 × 10⁸ CFU/mL, three times a week; CONT + PROB), (iii) a high-fat diet (HFD), or (iv) a high-fat diet with probiotics (HFD + PROB) for 13 weeks. The HFD group showed significant liver alterations, including lipid accumulation, severe steatosis, hepatocellular ballooning, and an increase in Il6 relative gene expression, as well as an interaction effect on Sirt1 relative gene expression (p < 0.05). Nevertheless, these changes were not mitigated by probiotic supplementation (p > 0.05). Additionally, HFD-fed mice exhibited significant alterations in adipose tissue (p < 0.05), such as increased tissue weight, a lower number of adipocytes per area, and larger adipocyte size per area, with no significant effect of the probiotic observed (p > 0.05). In the liver, high TBARS levels were found in the HFD group, and a probiotic supplementation effect on sulfhydryl levels was observed only in the HFD + PROB group (p < 0.05). Unlike, in adipose tissue, redox status was not affected by diet or supplementation (p > 0.05). In conclusion, our results demonstrated the pro-inflammatory effects of an obesogenic diet and suggest that Lact. rhamnosus LB1.5 supplementation contributes only to the enhancement of liver redox status, improving antioxidant defenses by increasing sulfhydryl levels.