ABSTRACT
Objective To investigate the bystander effect injury to lung-heart-liver-spleen caused by 12C6+ beam radiation,and explore the prevention and treatment effect of Guiqiyiyuan ointment on the injury and its mechanism.Methods Ninety healthy male Wistar rats were randomly divided into 3 groups:NC group (normal control,normal saline 2ml/kg,n=30),SR group (simple radiation,8Gy,2ml/kg,n=30),GO group (Guiqiyiyuan ointment 11.83g/kg,radiation,8Gy,n=30).All the rats received 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 heart,liver and spleen were taken.The malonaldehyde (MDA),glutathione (GSH),glutathione peroxidase (GSH-Px),superoxide dismutase (SOD) contents were measured by colorimetry,DNA methylation rate was assayed by ELISA,and the expressions of Dnmt1,Dnmt3a and Dnmt3b were detected by immunohistochemistry.Results Compared with NC group,the contents of SOD,GSH and GSH-Px decreased (P＜0.01),MDA increased (P＜0.01),the level of DNA methylation decreased (P＜0.01),and the expressions of Dnmt1,Dnmt3a and Dnmt3b increased in SR group (P＜0.01).Compared with SR group,the contents of SOD,GSH and GSH-Px increased (P＜0.01),MDA decreased (P＜0.01),the level of DNA methylation increased (P＜0.01),and the expressions of Dnmt1,Dnmt3a and Dnmt3b decreased in GO group (P＜0.01).Dnmtl,Dnmt3a and Dnmt3b proteins were expressed in the cytoplasm of myocardial cells,hepatocytes and peripheral B cells of the white pulp in spleen,in all the groups.The color of NC group was light brown-brown,showing a weak positive expression.The color of SR group was brown-brown,showing a strong positive expression.The color of GO group was light brown-tan,showing a moderate positive expression.Conclusion The Guiqiyiyuan ointment can reduce the bystander effect caused by the 12C6+ beam radiation,and its mechanism is related to improving the oxidative stress reaction and the level of DNA methylation.