Effects of Anti-Inflammatory Therapy on Bursting Pressure of colonic Anastomosis in Dextran Sulfate Sodium Induced Colitis in Mice

Background: The aim of this experimental study was to evaluate the effect of colitis and anti inflammatory therapies, respectively, on the healing of colonic anastomoses in mice. Methods: Eighty four female C57BL/6 mice where randomized into eight groups; four groups continued receiving plain tap water and four groups receiving dextran sulfate sodium. Intraperitoneal treatment was given for 14 days with placebo, prednisolone (2 mg/kg bodyweight), azathioprine (5 mg/kg bodyweight) or infliximab (5 mg/kg bodyweight) until surgery with transsection of the colon and an end to end colonic anastomosis was performed. All mice were sacrificed on day 2 and bursting pressure measurements were recorded. Results: In the DSS group the mice receiving placebo (n=4) had a more active inflammation with a bowel weight of 12.8 (10.6-15.0) mg/mm, which differed significantly from all the other therapy arms; prednisolone 8.1 (7.5-9.1) mg/mm (p=0.014), azathioprine 8.2 (7.0-8.5) mg/mm (p=0.0046), infliximab 6.7 (6.4-7.9) mg/mm (p=0.0055). Bursting pressure for the placebo group was 90.0 (71.5-102.8) mmHg and did not differ from the azathioprine or infliximab groups, 84.4 (70.5-112.5) and 92.3 (75.8-122.3) mmHg respectively. In contrast bursting pressure for the prednisolone-treated group was decreased compared to placebo, 55.5 (42.8-73.0) mmHg (p=0.0004), as well as compared with azathioprine (p=0.0004) and infliximab (p=0.0015). Conclusions: All given therapies had effect on the DSS-induced colitis. A severe decrease in bursting pressure of a colonic anastomosis was seen after preoperative steroids but we found no effect of azathioprine or infliximab. Thus, AZA and IFX may not increase the risk for anastomotic complications per se; the need for these therapies may rather be seen as markers of severe IBD with increased risk of surgical complications.