The effect of Bosentan on healing of colonic anastomosis

Ischemia is the most important factor compromises wound healing in colonic anastomosis. Mesenteric vessels are ligated at first while performing colonic resection and following anastomosis. Therefore blood supply of the related segments of colon temporarily interrupted and ischemia can easily occur. This study was carried out to explore whether Bosentan, an endothelin-receptor antagonist, can eliminate vasoconstruction, increase blood flow in the splanchnic area and anastomotic region and therefore possibly facilitate wound healing and prevent intra-abdominal adhesion formation.

Study is conducted on 30 female Wistar-Albino rats weighing 180-240 gr. Rats were allocated into three groups. Group 1 (n = 10) recevied full-thickness resection of the left colon and end-to-end anastomosis. In Groups 2 (n = 10) and 3 (n = 10), vessels of 2-3 cm segment of the left colon were ligated, indications of necrosis of that segment were expected, followed by resection and end-to-end anastomosis. Two milliliter of saline and 5 mg/kg Bosentan was given intraperitoneally in Group 2 and 3, respectively. On postoperativ day 6, intra-abdominal adhesions were scored. Healing of anastomosis, anastomotic bursting pressures, tissue hydroxyproline levels and histopatologically healing scores were assessed.

Macroscopic adhesion score in Group 3 was lower than the remained groups (p < 0.05). Tissue hydroxyproline levels were significantly higher in Group 3 compared to the Groups 1 and 2 (p < 0.001). Mean anastomotic bursting pressures were 200 mmHg, 164 mmHg and 240 mmHg in Groups 1, 2 an 3, respectively (p < 0.05 between Groups 1 and 3; p < 0.001 between Groups 2 and 3). Histopathologically, healing scores of Group 1 were significantly higher than the other groups (p < 0.05 group 1-3, group 2-3).

Bosentan increases anastomotic healing of ischemic colonic anastomosis and decreases intra-abdominal adhesion formation.