Effect of surgical trauma on muscle protein synthesis in the rat

Abstract

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.

Separation and identification of rat skeletal muscle proteins using two-dimensional gel electrophoresis and mass spectrometry

“…Discordant changes in muscle protein synthesis and/or protein degradation lead to either protein loss or accumulation. Examples include malnutrition [2], cancer [3], sepsis [4] and endocrine disorders [5] on the one hand, and growth [6], wound healing [7] and work-induced hypertrophy [8] on the other.…”

“…A further limitation concerns the analysis of abdominal skeletal muscle. This site was chosen because of its relevance to studies on the healing of surgical wounds [7,47]. However consideration needs to be given to the complex differences between different muscles, particularly in relation to their fibre-type composition.…”

Increased Collagen Synthesis Rate during Wound Healing in Muscle

“…Its validity depends crucially on all free proline pools in the body being flooded by the large dose of proline that was injected, so that the specific activity of free proline rapidly reaches a steady state value which is similar in all tissues and in the plasma and is maintained relatively constant throughout the 30 minute period of incorporation of labelled proline into protein. This is analogous to the flooding dose phenylalanine method [14] that is commonly used to measure the average synthesis rate of mixed proteins in tissues and indeed was used in our previous experiments to measure muscle protein synthesis rate during wound healing [3], [4]. The effectiveness of the flooding procedure in the present experiment was demonstrated by the equilibration of specific activity of free proline between the muscle samples and the plasma (see Table 1 ).…”

“…Relatively little is known about the changes in the rates of protein synthesis and breakdown that result in this net deposition of protein. We have previously measured the rate of protein synthesis in muscle during the healing of a surgical wound in vivo and found a substantial increase (70 – 150%), starting 48 hours after the operation and continuing at least until day 7 [3], [4]. Moreover, this increase in protein synthesis was not affected by malnutrition [4], suggesting that increased protein synthesis has a high biological priority.…”

Some aspects of the metabolic response to surgical trauma

“…Blunt trauma to the limbs had no effect on food intake, whereas abdominal surgery depressed food intake for several days. There is some evidence that the magnitude of the decrease is related to the severity of the operation, with hysterectomy (Bosagh Zadeh & Emery, 1997) causing a greater and more prolonged reduction in food intake than simple laparotomy (Emery & Ghusain-Choueiri, 1994).…”