辐射损伤小鼠皮肤缺损模型愈合评价

Evaluation of wound healing of skin defect in mice with radiation injury

目的建立小鼠不同全身辐射剂量合并皮肤缺损模型,研究全身辐射对皮肤创面愈合的影响,探讨其病理生理学变化。方法采用180只雌性昆明种小鼠,60 Coγ射线一次性均匀照射4、6、8 Gy,照后30 min内,于小鼠背部制作1.5 cm×1.5 cm方形全层皮肤缺损伤口,构建不同全身放射剂量合并皮肤缺损动物模型(n=50),以单纯皮肤缺损作为对照组(n=30),各组动物于伤后3、5、7、10、14 d分别处死6只,取伤口全层皮肤组织,组织病理学检查伤口区炎细胞、成纤维细胞、新生毛细血管数量的变化;应用图像分析系统定量分析未愈伤口残余面积,统计14 d内各组动物存活率及体质量变化。结果 6 Gy放创组7 d和14 d的存活率分别为75%和55%,8 Gy放创组7 d时存活率仅33%,至10 d全部死亡。伤后14 d内,随辐射剂量的增加,放创组体质量较伤前降低程度愈加明显。全身辐射对皮肤创面愈合延迟随辐射剂量增加而加重:6、8Gy放创组2 d与对照组相比残余面积增大(P<0.01),4 Gy放创组伤后8 d与对照组相比残余面积增大,差异有统计学意义(P<0.05)。H-E染色显示:与对照组相比,放创组小鼠伤口早期炎症反应受抑,成纤维细胞和新生毛细血管数量增多明显滞后,肉芽组织形成延迟,上皮覆盖滞后。结论 6 Gy 60Coγ射线全身放射合并皮肤缺损伤的动物模型可为放创复合伤难愈机制的研究和早期的实验治疗提供研究平台。

Objective To establish mouse models of total body irradiation（TBI） with different doses of 60Co γ radiation combined with skin defect,so as to investigate the influence of TBI on wound healing and the pathophysiological changes in combined radiation injury and skin defect.Methods A total of 180 female Kunming mice were irradiated with a single dose of 4,6 or 8 Gy 60Co γ ray.Within 30 min after irradiation,a full thickness square wounds（1.5 cm×1.5 cm） was made on the back of mice to establish animal models of TBI combined with skin defect（n=50）,another 30 mice with pure skin defect were used as controls（n=30）.Mice in each group were sacrificed on the 3rd,5th,7th,10th and 14th day after injury,each time 6 mice,and the full thickness wounds were harvested.Histological method was used to evaluate the changes of inflammatory cells,fibroblasts and new blood capillaries in the wounds.Image analysis system was used to analyze the areas of the residual wounds.The survival rates and body weight changes of mice within 14 days were analyzed in all groups.Results On the 7th and 14th day after injury,the survival rates of mice in the 6 Gy group were 75% and 55%,respectively.While in the 8 Gy group the survival rate of mice was only 33% on the 7th day,and all the animals died by the 10th day.Within 14 days after injury,the body weight loss of mice demonstrated an increasing tendency with the increase of radiation doses（4,6,and 8 Gy groups）.TBI delayed wound healing in mice with the increase of irradiation dose.The unhealed areas in the 6 and 8 Gy groups were larger than that in the control group on the 2nd day（P0.01）,and that in 4 Gy group was significantly larger than that in the control group on the 8th day（P0.05）.H-E staining showed that the early inflammatory responses were inhibited,the increase of fibroblasts and new capillaries were greatly delayed,and the granulation tissue formation and reepithelialization were slowed down in the TBI group compared with the simple wound group.Conclusion Animal models of TBI with 6 Gy 60Co γ-ray combined with skin defect can serve as a platform to study the mechanism of difficult healing and early treatment of radiation injury combined with skin defect.