Hindlimb muscle atrophy occurs from short-term undernutrition in rats.

The purpose of this study was to examine the effect of short-term (7 days) undernutrition on Type I (soleus) and Type II (plantaris, gastrocnemius) muscles in rats. Male Sprague-Dawley rats (N = 20) were randomly assigned to one of two groups: a control group (n = 10) in which animals were allowed to have water and pellets ad libitum and an undernourished group (n = 10) in which animals were allowed to have 37% of the total food intake of the control group and water ad libitum. Body weight and food intake were measured daily. After 7 days, rats were anesthetized and the soleus, plantaris, and gastrocnemius muscles and liver were dissected. Body weight, liver weight, muscle weight, Types I and II fiber cross-sectional area, and myofibrillar protein content were determined. After 7 days of undernutrition, the undernourished group showed significant decreases (p < .05) compared to the control group in body weight, liver weight, muscle weight of soleus, plantaris, and gastrocnemius muscles, and cross-sectional areas of Types I and II fiber of the plantaris and gastrocnemius muscles.