Low-Magnitude High-Frequency Vibration Decreases Body Weight Gain and Increases Muscle Strength by Enhancing the p38 and AMPK Pathways in db/db Mice

Objective: To evaluate the effect LMHFV on body weight gain, NAFLD and muscle strength and explore effect in mitochondrial biogenesis, AMPK alpha and p38 pathways. Methods: Vibration platform used in this study provides specific whole-body cyclic mechanical stimulation at low magnitude (0.3 g) and high frequency (50 Hz). Diabetic mice (8-9 mice per group) (C57BL/KsJ-m+/+Lepr(db)) were randomly divided into untreated group (no vibration) and two vibration groups. Lean mice (8 mice) were used as non-diabetic control for both groups. Two diabetic vibration groups received LMHFV every day for 20 min/day and 40 min/day separately. Results: After 8 weeks of treatment, results showed that body weight, liver weight, fat pad weight, glucose level and insulin level were lower in vibration group when compared with the untreated group. The ratio of fat in liver was significantly decreased after vibration treatment. Muscle strength was significantly increased after vibration. Mitochondrial biogenesis-related gene expression was increased in soleus, gastrocnemius and liver. AMPK alpha mRNA expression level was increased in soleus and gastrocnemius after vibration treatment. p38 and AMPK alpha mRNA expression level and protein expression level in liver were enhanced with vibration treatment. Moreover, phosphorylation of p38 and AMPK alpha was enhanced in liver. Conclusion: LMHFV applied in our study decreases body weight gain and improves muscle strength and NAFLD in diabetic mice which were partly through improving mitochondrial biogenesis by enhancing p38 and AMPK alpha pathway.