Dose-effect relationships in total body irradiation on the healing of cutaneous wounds

Objective To study the effects of dosages of total body irradiation on the healing process of cutaneous wounds and to observe the changes of wound area at different periods after injury.Methods The entire body irradiation from a ^60Co γ-ray source was performed on Wistar rats. The single dosage varied from 1 to 8 Gy. Within 1 h after irradiation, two whole thickness circular cutaneous wounds corresponding to 2. 5% of total body surface area (φ=22 mm) were produced on the back of the animals (combined injury groups ). Same wounds were produced on rats with noirradiation (single wound group). Wound healing was observed at different points after injury.Results After total body irradiation with the dose of 1,2,3,4,5,6, 7 or 8 Gy, the wound healing was obviously retarded as the dosages increased. The wound area remained was larger in the large dosage groups than in the small dosage groups. Seven days after injury, there was 33. 5% wound surface left unhealed in the single wound group, whereas in the combined injury groups, 35. 4%,38. 1%, 41.6%, 48. 8%, 53. 9%, 63. 7%, 69.2% and 73. 9% of the wound surfaces remained unhealed, respectively. Statistical analysis showed marked correlations between the various times after total body irradiation and various dosages to the percentage of unhealed wound surface. Nine dose-effect relation formulae were deduced according to the statistical results.Conclusions In soft tissue trauma combined with radiation injury, the delay of wound healing is related to the dose of radiation inflicted. It is also related to the time between iniurv and time of observation.