Effects of ozone preconditioning on recovery of rat colon anastomosis after preoperative radiotherapy

Abstract

Background. Anastomotic leakage is a devastating complication of colorectal surgery. Neoadjuvant radiotherapy for colorectal cancer can affect the mechanical and biochemical parameters of anastomotic healing. It has been reported that ozone increases antioxidant enzyme activity and stimulates adaptive processes to oppose the pathophysiologic conditions mediated by reactive oxygen species (ROS). Objectives. The objective of this study was to investigate the effect of controlled administration of ozone on the healing of anastomosis and the activation of antioxidant enzymes in the colon after radiotherapy. Material and methods. Rats (n = 48) were randomly assigned to the following groups: control groups (1 and 2), saline-treated and irradiated (IR) groups (3 and 4) and ozone oxidative preconditioning (OOP) and IR groups (5 and 6). Rats were exposed to whole-body IR (6 Gy) after pretreatment with either saline or ozone. Rats in groups 1, 3 and 5 were euthanized on postoperative day 3, whereas those in groups 2, 4 and 6 were euthanized on postoperative day 7. The anastomoses were performed on day 7 post-IR. The anastomotic segment was resected to measure hydroxyproline (HPO) content, myeloperoxidase (MPO) activity and malondialdehyde (MDA) concentration and for histopathological evaluation. Results. The mean bursting pressure of the groups that underwent radiotherapy was lower than that of the control groups (p < 0.001). In groups 5 and 6, the tissue HPO concentrations were higher than those in groups 3 and 4. Although mean values for MPO activity in groups 5 and 6 were higher than those in groups 3 and 4, the differences were not significant. Regarding oxidative damage markers, MDA concentrations were significantly lower in group 5 than those in group 3. Conclusions. In this experimental model, OOP exerted favorable effects on colon anastomotic healing after radiation exposure.