归芪益元膏对重离子辐射损伤模型大鼠肺肾旁效应的影响

Bystander effects of Guiqiyiyuan Ointment on lung and kidney of rats damaged by heavy ion radiation

目的探讨归芪益元膏防治重离子(12C6+)束辐射肺肾旁效应的作用机制,为临床辐射损伤防护提供新的思路。方法健康雄性Wistar大鼠60只,随机分为正常对照组(NCG组)、单纯辐射组(SRG组)、归芪益元膏组(GOG组),每组20只。灌胃给药7d,12C6+束辐射右侧肺部造模,造模后48h处死,取大鼠左肺、左肾及右肾组织,ELISAlike法检测DNA甲基化率,HE染色观察组织病理学改变,免疫组织化学法检测Dnmt1、Dnmt3a、Dnmt3b的表达。结果与正常对照组比较,单纯辐射组大鼠DNA甲基化水平显著降低(P<0.01);左肺有炎症,左右肾无异常;Dnmt1、Dnmt3a、Dnmt3b表达明显升高(P<0.01)。与单纯辐射组比较,归芪益元膏组大鼠DNA甲基化水平升高(P<0.01);左肺炎症减轻;Dnmt1、Dnmt3a、Dnmt3b表达降低(P<0.01)。Dnmt1、Dnmt3a、Dnmt3b蛋白均在支气管黏膜上皮细胞、肾小管上皮细胞的胞质内表达,各组均可见;正常对照组呈浅褐色-褐色染色,为弱阳性表达;单纯辐射组呈褐色-棕色染色,为强阳性表达;归芪益元膏组呈浅褐色-棕褐色染色,为中等程度阳性表达。结论归芪益元膏可减轻12C6+束辐射造成的肺肾旁效应,其机制可能与调控DNA甲基化水平有关。

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.