Abstract: Objective:To investigate the effect of Qingre Shengji ointment on the incidence of acute radiation dermatitis, intercellular adhesion molecule-1 (ICM-1) and neovascularization in rats with breast cancer after radiotherapy.Methods:40 SPF SD female rats were selected and randomly divided into normal group (group N), model group (group M), aloe vera gel group (group A), and Qingre Shengji ointment group (group H), with 10 rats in each group.The breast cancer model of group M, group A and group H was established by inadministration of dimethylbenzanthracene, radiotherapy was given after successful modeling, then aloe vera gel was applied directly to group A, and Qingre Shengji ointment was applied directly to group H on the affected area.Group N and group M were concurrently administered the same volume of normal saline via gastric lavage, the incidence of acute radiation dermatitis of rats was calculated, the wound curve was drawn, the skin tissue pathological morphology was detected by HE staining, the expression of ICM-1 protein was detected by western blotting, and the related indicators of neovascularization were analyzed by immunohistochemical staining and image analysis.Results:Compared with group M, the incidence of acute radiation dermatitis in groups A and H decreased (P< 0.05), and the decrease in group H was significantly greater than that in group A (P< 0.05).Compared with group M, the wound incidence curve of group A and Group H significantly decreased(P< 0.05), and the decrease of group H was significantly greater than group A(P< 0.05).The skin tissues and fibroblasts of rats in group N were normal and complete, the spinous cells were evenly distributed, the epidermis was smooth and flat, the appendages of hair follicles, sebaceous glands, sweat glands and other appendages developed normally, and no widening or narrowing of spacing was observed.The skin epidermis in group M was uneven and partially detached, the epidermis was necrotic, the appendages of the skin in the dermis disappeared, and the structure was disorganized.A large number of large and deformed radioactive fibroblasts and a large number of inflammatory cells were infiltrated, and a small number of neovascularization could be seen.Compared with group M, pathological symptoms were significantly improved in group H and group A, and neovascularization significantly increased.Compared with group N, the expression of ICM-1 protein in the exposed skin tissues of group M significantly increased(P< 0.05), while the expression of ICM-1 protein in the exposed skin tissues of groups H and A significantly decreased compared with group M(P< 0.05), and the decrease in group H was significantly greater than that in group A(P< 0.05).Compared with group N, there was no significant difference in the number of new microvessels in group M(P> 0.05), and the gray value of vascular endothelial growth factor(VEGF)and its receptor(VEGFR)in skin tissues at the exposed site significantly increased(P< 0.05).Compared with group M, the number of new microvessels in groups H and A significantly increased.The gray values of VEGF and VEGFR in the exposed skin significantly decreased (P< 0.05), and the changes in group H were significantly greater than those in group A(P< 0.05).Conclusion:Qingre Shengji ointment is effective in reducing the incidence of acute radiation dermatitis, reducing the expression of ICM-1 and promoting neovascularization in breast cancer rats after radiotherapy.