低剂量辐射联合环磷酰胺对荷瘤鼠DNA损伤的影响

目的研究低剂量辐射联合环磷酰胺对荷瘤鼠外周血淋巴细胞DNA损伤的影响。方法荷瘤鼠随机分为对照组、CTX化疗组(CTX组,40mg/kg)和低剂量照射联合CTX组(LDR CTX组),环磷酰胺给予前6h行5cGy的低剂量照射,连续3 d。采用中性单细胞凝胶电泳检测低剂量辐射联合化疗后对荷瘤鼠外周血淋巴细胞DNA双链断裂的情况。观察了尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩等指标的变化。结果LDR CTX组其尾长、彗星长、头DNA%、尾DNA%、尾矩、Olive尾矩均比CTX组明显减小,各项指标差异均有显著性(P<0.05)。结论荷瘤鼠预先接受低剂量全身照射能减轻环磷酰胺治疗后外周血淋巴细胞DNA损伤。

Effects of Low Dose Radiation Combined with Cyclophosphamide on DNA Damage of Tumor-bearing Mice

Objective To investigate the effects of low dose radiation combined with Cyclophosphamide on DNA damage of peripheral blood lymphocytes of tumor-bearing mice.Methods Neutral single-cell gel electrophoresis(SCGE) was used to detect the effects of low dose radiation combined with Cyclophosphamide on DNA double strand breaks of peripheral blood lymphocytes of tumor-bearing mice,which were divided into three groups:control group,CTX group(40?mg/kg)and LDR CTX group.Low dose radiation(5cGy) was delivered 6h before chemotherapy for three days.We observed the changes of tail length,comet length,percent head DNA,percent tail DNA,tail moment and Olive tail moment.Results The amount of tail length,percent tail DNA,tail moment and Olive tail moment in low dose radiation combined with Cyclophosphamide group were significantly lower than those of Cyclophosphamide group(P<0.05).Conclusion Low dose radiation delivered before Cyclophosphamide can reduce DNA damage of peripheral blood lymphocytes of tumor-bearing mice.