Effects of low-intensity endurance exercise and low-dose lithium chloride administration on muscle atrophy in high-fat diet induced obese rats.

Purpose: We provided basic scientific data to help prevent and treat sarcopenia in young obese individuals by observing the effects of low-intensity endurance exercise and low-dose lithium treatment on skeletal muscle atrophy in rats with high-fat diet (HFD)-induced obesity.

Methods: Six-week-old male Wistar rats were fed an HFD for 8 weeks to induce obesity. Next, rats were randomly assigned to four groups and treated with lithium or exercise for 8 weeks. Lithium (10 mg/kg lithium chloride [LiCl], gavage) or endurance exercise (17 m/min, 30 min/day) was performed once daily for 5 days per week. After the experiment, body composition was measured using dual-energy X-ray absorptiometry (DEXA), and tissues were extracted after anesthesia and analyzed.

Results: Endurance exercise or 8 weeks of lithium had no significant effect on the morphology of the liver and kidney tissues in rats. Although lithium and endurance exercises alone increased the lean body mass, the difference was not statistically significant. However, combined treatment with lithium and endurance exercise significantly increased the lean body mass. No significant difference was noted in the abdominal fat mass between the groups. Eight weeks of lithium or endurance exercise did not affect the mechanistic target of rapamycin (mTOR) expression in the skeletal muscles of obese rats. However, it significantly inhibited the FOXO1 signaling pathway, a muscle atrophy signal, and reduced the expression of tumor necrosis factor (TNF) α.

Conclusion: A combination of low-intensity endurance exercise and low-dose lithium prevented muscle atrophy (wasting) by inhibiting the FOXO1 signaling pathway in skeletal muscles. Therefore, light walking and lithium supplementation in daily life are expected to prevent muscle atrophy in obese patients. However, it is difficult to draw definitive conclusions based on the results of this study alone and additional research is warranted.