Opposite Effects of Interleukin-2 on Normal and Transfusion-Suppressed Healing of Experimental Intestinal Anastomoses

OBJECTIVE: This study was done to investigate whether administration of interleukin-2 (IL-2) can abrogate the negative effects of blood transfusions on anastomotic healing. SUMMARY BACKGROUND DATA: Recently, the authors showed that blood transfusion severely impairs anastomotic repair and significantly increases the susceptibility to intra-abdominal septic complications in rats. It has been reported that blood transfusions suppress IL-2 production and that IL-2 may stimulate wound healing. METHODS: Lewis rats underwent resection and anastomosis of both the ileum and colon. Subsequently, they received either 3 mL of saline (control and IL-2 groups) or 3 mL of blood from brown Norway donors (transfusion and transfusion/IL-2 groups) intravenously. From the operation onward, the animals in the IL-2 and transfusion/IL-2 groups received daily injections of 5.4 x 10(5) IU of IL-2 in dextrose solution subcutaneously; the rats in the other groups received only the dextrose solution. The animals were killed 3 or 7 days after the operation and examined for septic complications and anastomotic repair. RESULTS: Transfusion led to an enhanced incidence of anastomotic abscesses, which was almost completely abrogated after IL-2 administration. The anastomotic strength was consistently and significantly reduced after transfusion. Seven days after surgery, the anastomotic strength was completely restored by IL-2 treatment. For instance, the average bursting pressure (+/- the standard deviation) of the ileal anastomoses in the control, transfusion, and transfusion/IL-2 groups were 86 +/- 15, 32 +/- 8,* and 63 +/- 10 mmHg* [symbol: see text] on day 3 and 293 +/- 36, 227 +/- 16,* and 299 +/- 19 mmHg on day 7, respectively (where * = significant vs. control group and [symbol: see text] = significant vs. transfusion group). In addition, IL-2 administration elevated the anastomotic hydroxyproline content, which was significantly decreased by transfusion alone, to the level found in the control group. The administration of IL-2 to control animals resulted unexpectedly in a significant reduction in anastomotic strength. CONCLUSIONS: Exogenous IL-2 reverses the negative effects of blood transfusions on anastomotic repair, but it impairs healing under normal conditions.