Effect of surgical trauma on muscle protein synthesis in the rat

The rate of protein synthesis in skeletal muscle was measured in vivo in rats at various times during the first 2 days after abdominal surgery. Protein synthesis in abdominal muscle at the site of the wound was slightly reduced 2 h after operation, had returned to normal by 24 h and was massively increased by 48 h after surgery. In contrast, there was no change at any time in the rate of protein synthesis in either the gastrocnemius muscle or abdominal muscle distant from the wound site. Surgery had no effect on the weight or protein content of the gastrocnemius muscle, although urinary nitrogen excretion was increased relative to food intake, indicating the presence of a net catabolic response. Changes in whole-body protein turnover in response to uncomplicated abdominal surgery are thus likely to reflect the anabolic processes of wound healing and repair as well as any catabolic response in uninjured tissues.