Diet Induced Obesity Alters Muscle Spindle Afferent Function in Adult Mice

Individuals with obesity are more likely to fall and exhibit balance instability. The reason for this is likely multifactorial, but there is some evidence that sensory function is impaired during obesity. We tested the hypothesis that muscle proprioceptor function is compromised in a mouse model of diet induced obesity. We used an in vitro muscle-nerve preparation to record muscle spindle afferent responses to physiological stretch and sinusoidal vibration. We compared the responses of mice on a control diet (10% kcal fat) with those eating a high fat diet (60% kcal fat) alone or in combination with either aspirin (120mg/kg/day in drinking water) or rosiglitazone (0.01% in chow) for 10 weeks. Following high fat diet feeding, adult mice exhibited decreased muscle spindle afferent responses to stretch and lower dynamic sensitivity. Treatment with aspirin or rosiglitazone did not completely rescue muscle spindle afferent responsiveness. Due to the importance of muscle spindle afferents to proprioception and motor control, decreased muscle spindle afferent responsiveness may contribute to balance instability during obesity. Future studies should test this hypothesis in the human population