Role and mechanism of radiological protection cream in treating ra- diation dermatitis in rats

OBJECTIVE： To explore the role and mechanism of a radiation protection cream （Rp） in the treatment of radiation dermatitis, and to accumulate neces- sary technical information for a new drug report on Rp. METHODS： High-performance liquid chromatogra- phy was used to establish the method of measur- ing the main effective ingredients of sovereign andadjuvant herbs of Rp drugs, and to formulate the draft quality standards of Rp. A total of 48 Sprague-Dawley male rats were randomly divided into the Model, Trolamine cream （Tc）, Rp and Blank groups according to a random number table meth- od. The skin of each rat＇s buttocks was irradiated us- ing an electron linear accelerator to establish an acute radiation dermatitis model. The histological changes were observed under light microscopy and electron microscopy during wound healing and the effect of Rp on rat fibroblast Ku70/80 gene expression was detected at the transcriptional level. RESULTS： Pathological examination revealed that Rp protected the cellular and subcellular structures of skin after irradiation, promoting the proliferation and restoration of collagen fibers. Ku70/80 mRNA expression levels in the Rp and Tc groups were higher than that in the model group （P〈0.05）. More- over, The majority of grade radiation dermatitis rela- tive to the Model, Rp and Tc groups for reducing grade Ⅲ and Ⅳ dermatitis efficiency were 85.7% and 69.2% （P〈0.05）, respectively. The efficacy of Rp group in treating radiation dermatitis was better than the Trolamine cream group by 16..5% （P〈0.05）. CONCLUSION： Compared with Tc, Rp had certain advantages in the efficacy and performance to price ratio. Thus, Rp is considered an effective alter- native formulation for the prevention and treat- ment of radiation dermatitis.