The combined effects of probiotic and high-intensity interval training on memory function in high fat diet-fed rats

This study aimed to investigate whether the probiotic Lactobacillus rhamnosus GG (LGG) (alone or combined with high-intensity interval training (HIIT)) could improve cognitive, electrophysiological changes, oxidative stress and metabolic parameters in HFD-fed rats.

Rats were randomly divided into four groups (n = 8): HFD group, HFD + LGG group, HFD+ HIIT group, and HFD + LGG+ HIIT group. Rats were fed HFD daily for a period of 16 weeks, during which LGG (1 × 10¹⁰ colony forming unit (CFU)/ rats, orally), and HIIT protocol were administered four times a week on alternating days. At the end of study, assessment of social behavior, memory function, and Long-term potential (LTP) were performed using three-chambered apparatus, Y-maze task, and electrophysiology technique, respectively. Next, oxidative stress, lipid profiles, and liver enzymes were evaluated with routine kits.

Both LGG and HIIT alone or in combination improved working memory, social memory, and LTP in HFD-fed rats. In addition, both LGG and HIIT alone or in combination increased the hippocampal levels of superoxide dismutase, catalase, and increased the serum levels of high-density lipoprotein (HDL), and decreased the serum levels of leptin, triglyceride, cholesterol, low-density lipoprotein (LDL), aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) in HFD-fed rats.

The combination of LGG and HIIT provides a multi-pathway intervention that improves HFD-induced memory impairments by concurrently targeting oxidative stress, dyslipidemia, and hippocampal synaptic function. This supports the potential of combined lifestyle and microbiome-based therapies for preventing metabolic and cognitive disorders.