Effects of 5-fluorouracil and zinc on healing of colonic anastomoses in rabbits

Objective: To find out if 5-fluorouracil (5-FU) given intraperitoneally to rabbits impaired the healing of colonic anastomoses, and whether giving zin c might reverse the effect. Design: Laboratory study. Setting: Teaching hospital, Turkey. Animals: 32 New Zealand white rabbits. Interventions: All animals had 1 cm of large bowel resected 10cm proximal t o the peritoneal reflection and continuity restored by end-to-end anastomos is. They were divided into four groups and given intraperitoneal injections of saline (control group), 5-FU 10mg/kg/day in a concentration of 5mg/ml s aline (5-FU alone group), zinc 2mg/kg/day (zinc alone group), and the same doses of 5-FU and zinc (5-FU + zinc group). The injections were given immed iately after operation and daily for 4 days. The rabbits were killed at 7 d ays. Main outcome measures: Bursting pressures, tissue hydroxyproline concentrat ions, tissue zinc concentrations, and light and electron microscopic appear ances. Results: Six rabbits died of the complications of anaesthesia and 4 of seps is leaving 7, 6, 7, and 6 rats in the four groups respectively. Mean (SD) a nastomotic bursting pressures were significantly reduced in the 5-FU group compared with controls (5 (2) compared with 7 (1) mm Hg, p: 0.05) and colla gen synthesis (indicated by reduced tissue hydroxyproline concentrations) w as also decreased (7.1 (0.9) compared with 9.1 (1.5), p < 0.05). Rabbits gi ven 5-FU + zinc had significantly higher bursting pressures than those give n 5-FU alone (9 (2) compared with 5 (2), p: 0.01). Bursting pressures were also significantly higher in those given zinc alone, but hydroxyproline con centrations were similar to those in the control group. Histological examin ation showed that 5-FU alone significantly impaired the healing process, an d those in the 5-FU + zinc group healed better than those in the 5-FU alone group. Conclusions: 5-FU given intraperitoneally significantly impaired the healin g of colonic anastomoses in rabbits, and zinc reversed this effect.