Huanglian Jiedu Plaster Ameliorated X-Ray-Induced Radiation Dermatitis Injury By Inhibiting HMGB1-Mediated Macrophage-Inflammatory Interaction

Objective:Radiation dermatitis(RD)is a common skin injury disease in tumor patients during radiotherapy,which is manifested as erythema,edema,peeling and even ulcer.It seriously affects the quality of life of patients and even leads to the delay or interruption of tumor treatment.Huanglian Jiedu Plaster(HJP)is a traditional Chinese medicine paste with anti-inflammatory and anti-tumor pharmacological activities.However,the mechanism of HJP in treating radiation dermatitis is still unclear.In this study,a mouse model of radiation dermatitis was established by X-ray irradiation in vitro,and a JB6 radiation inflammation model was established in vivo.The experimental methods and indicators such as HE staining,immunohistochemical staining,Western Blot,Real-time PCR,ELISA,CCK8 toxicity analysis,immunofluorescence labeling,Transwell co-culture were used to explore the therapeutic effect of HJP on X-ray radiation dermatitis,And how HJP can improve the inflammatory reaction and skin damage caused by radiation dermatitis.Methods:In this study,RD mouse models were established through continuous irradiation with X-ray(800c GY)on the right hind limb of mice for5 days,and the treatment group mice was applied HJP to the irradiated skin for15 days from modeling.An inflammatory cellular model was induced through irradiation with X-ray(100cGY)in JB6 cells and a co-culture system of JB6 cell and macrophage was established to examine the effect and mechanism of HJP on the inflammatory interaction of these two cells.The activation of HMGB1-TLR4-NF-κB signaling pathway,and the levels of epidermal injury related factors and inflammatory cytokins were subsequently detected.Results:The results showed that HJP can significantly alleviate X-ray-induced skin injury,inhibiting skin inflammation and reducing the expression of inflammatory cytokins(IL-1β,IL-6,Tnf-α)and epidermal damage related factors(Integrin β1,CXCL9 and Cytokeratin17),as well as significantly down-regulated the protein level of HMGB1(a key DAMPs factor)in vivo and in vitro.Cell co-culture experiments demonstrated that HMGB1 released from X-ray-induced JB6 cells can promote inflammatory response of macrophage,which then feedback aggravate epithelial cell damage,notably,HJP can significantly improve radiation skin lesion by inhibiting HMGB1-mediated inflammatory interaction between epithelial cells and macrophages.Conclusion: In summary,these findings indicated the role of HJP in the treatment of RD by inhibiting the inflammatory interaction between macrophage and JB6 cells mediated by HMGB1,which may provide a reliable therapeutic method for RD.Furthermore,HMGB1 may be an effective target for HJP to inhibit inflammation and ameliorate skin damage in RD.