New and safe experimental model of radiation-induced neurovascular histological changes for microsurgical research

The aim is to create a new and safe experimental model of radiation-induced neurovascular histological changes with reduced morbidity and mortality for use with experimental microsurgical techniques. Seventy-two Sprague-Dawley rats (250-300 g) were divided as follows: Group I: control group, 24 rats clinically evaluated during six weeks; Group II: evaluation of acute side-effects (two-week follow-up period), 24 irradiated (20 Gy) rats; and Group III: evaluation of subacute side-effects (six-week follow-up period), 24 irradiated (20 Gy) rats. Variables included clinical assessments, weight, vascular permeability (arterial and venous), mortality and histological studies. No significant differences were observed between groups with respect to the variables studied. Significant differences were observed between groups I vs II-III regarding survival rates and histological changes to arteries, veins and nerves. Rat body weights showed progressive increases in all groups, and the mortality rate of the present model is 10.4% compared with 30-40% in the previous models. In conclusion, the designed model induces selective changes by radiotherapy in the neurovascular bundle without histological changes affecting the surrounding tissues. This model allows therapeutic experimental studies to be conducted, including the viability of microvascular and microneural sutures post radiotherapy in the cervical neurovascular bundle.