Effects of chronic renal failure on wound healing in rats. II. Microscopic study and hydroxyproline assay.

Incisional wounds of the abdominal skin, aponeurosis, stomach and colon were investigated microscopically for a comparison of the findings between uremic and normal rats. The grade of edema and number of inflammatory cells were increased in the rats with uremia and the granulation zone was also larger in the uremics. Hydroxyproline was assayed in the wound tissues by a modification of the technique of Stegemann and Stalder. The hydroxyproline level was lower in the uremics (p less than 0.05) only in the aponeurosis of the 5th postoperative day and in the colon of the 3.5th to 7th day. The correlation coefficient calculated for the blood urea level, biomechanical strength and hydroxyproline level was nil. If these results can validly be extrapolated to patients with chronic renal failure, careful management and avoidance of possible wound infections is of the greatest importance for surgical patients.