Intravenous butyrate and healing of colonic anastomoses in the rat

PURPOSE: Intracolonic infusions of short chain fatty acids promote healing of colonic anastomoses. Because the intravenous route may have wider clinical application, we studied the effect of intravenous n-butyrate on the mechanical strength of colonic anastomoses in the rat. METHODS: After placement of an indwelling intravenous catheter, the descending colon was transected and an anastomosis was performed. Rats were then randomized to receive total parenteral nutrition (TPN group; n = 15) or total parenteral nutrition plus 130 mM/l of n-butyrate (TPN+BUT group; n = 13). On the fifth postoperative day, bursting pressure and bowel wall tension of the anastomoses were measured in situ. Anastomotic tissues were analyzed for hydroxyproline. RESULTS: The TPN+BUT group had a significantly higher bursting pressure (107.5 +/- 30.3 vs. 83 +/- 41.0 mmHg; P = 0.04) and bowel wall tension (20.7 +/- 7.6 vs. 14.1 +/- 9.9 Newton; P = 0.03). Tissue hydroxyproline was not different between the two groups (TPN, 45.8 +/- 9.2, and TPN+BUT, 47.9 +/- 2.9 microg/mg tissue nitrogen). CONCLUSIONS: We conclude that intravenous butyrate improves mechanical strength of a colonic anastomosis without a detectable change in total collagen content.