THE EFFECT OF HIGH-FAT DIET ON MUSCLE STRETCH SENSITIVITY
Kassina Kim-Hayes1, Lubayana Elahi2, Krystle Shamai2, Samson Tang2, Katherine Wilkinson2.
1Macalester College, Saint Paul, MN, 2San Jose State University, San Jose, CA.
Obesity has become a prominent public health issue. Obese individuals have shown more trouble with balance and are more likely to fall than nonobese individuals. Balancing the body involves proprioception, the ability to sense one’s body position, which relies on muscle spindle afferents, nerves that innervate muscle spindles and detect muscle stretch to alert the brain of a muscle’s status. We believe that the difficulty in balance seen with obese individuals is in part due to these muscle spindle afferents. Our lab has previously shown insensitivity of muscle spindle afferents in male mice fed a high-fat diet. This insensitivity could help explain why obese individuals have impaired balance. We are testing the hypothesis that female mice fed a high-fat diet will not show similar impaired muscle stretch sensitivity like the male mice in our previous studies. To test this, we used a control group of mice that were fed a regular diet (10% kCal from fat), and a high-fat-diet group of mice (60% kCal from fat), all female. After dissection, we weighed the reproductive fat pads, spleen, and kidney, and measured blood glucose levels to compare how female mouse weight gain and metabolic markers differ from males. We then measured the response of the muscle spindle afferents to 3 stretch lengths by physically stretching the muscle to determine if high-fat female mice showed impaired stretch sensitivity. If our hypothesis is supported, the results could give us insight into human obesity and the cause of the proprioceptive difficulties that come with obesity.