Influence of standard heparin or low molecular weight heparin on healing of abdominal wounds and colonic anastomoses in rats.

The influence of standard heparin or low molecular weight (LMW) heparin on healing of abdominal wounds and colonic anastomoses was studied in rats. Subcutaneous injection of 1 XaI U/g b.w. of standard or LMW-heparin or 0.5 ml physiologic saline was given 12 hours preoperatively and daily for 3 or 7 days postoperatively. Breaking strength of the abdominal wound and the anastomosis was measured, as were haemoglobin and albumin in serum. Hydroxyproline as a measure of collagen and tissue dry weight was determined in standardized segments of colonic wall adjacent to the anastomosis. Except for significant increase in breaking strength of the anastomosis after 7-day injection of LMW heparin, no differences in the parameters of wound healing were found after 3 or 7 days. In rats receiving standard heparin there was increased bleeding tendency (reduced haemoglobin) compared with the LMW-heparin group and the controls. The administered heparin thus did not negatively influence healing, and standard and LMW-heparin did not differ in this respect.