Bystander effects of Guiqiyiyuan Ointment on lung and kidney of rats damaged by heavy ion radiation / 解放军医学杂志

ABSTRACT

Objective To investigate the mechanism of Guiqiyiyuan Ointment (GO) for preventing and treating 12C6+ beam radiation induced lung and kidney bystander effect to provide a new strategy for prevention and treatment of clinical radiation injury. Methods Sixty healthy male Wistar rats were randomly and equally divided into 3 groups NC group, SR group (simple radiation 2ml/kg), GO group(GO 2ml/kg intragastric administration for 7 days). The right side of the lung was modeled by 12C6+beam radiation. After modeling, the rats were killed at 48h. The left lung, left and right kidney tissues were taken from the rats. The DNA methylation rate was detected by ELISA assay, pathological changes were observed by HE staining, and the expressions of Dnmt1, Dnmt3a and Dnmt3b were detected by immunohistochemistry. Results Compared with the NC group, the level of DNA methylation was decreased significantly (P<0.01), the left lung showed inflammation, no abnormal finding was seen in the left and right kidneys, and the expressions of Dnmt1, Dnmt3a and Dnmt3b were significantly increased in the SR group (P<0.01). Compared with the SR group, the level of DNA methylation was increased significantly (P<0.01), the left lung inflammation became better, and the expressions of Dnmt1, Dnmt3a and Dnmt3b were significantly decreased in the GO group (P<0.01). Dnmt1, Dnmt3a and Dnmt3b proteins were expressed in the cytoplasms of bronchial and renal tubular epithelial cells in all the groups. The NC group presented as light brown-brown staining, showing a weak positive expression, the SR group as brown-brown staining, showing astrong positive expression, and the GO group as light brown-brown staining, showing a moderate positive expression. Conclusion The GO can reduce the bystander effect caused by 12C6+ beam radiation, and its mechanism is related to improving the level of DNA methylation.