小剂量γ射线累积照射对大鼠尿液中小分子代谢物影响

目的 探讨小剂量¹³⁷Cs γ射线累积照射对大鼠尿液中小分子代谢物的影响。方法 无特定病原体级健康雄性成年SD大鼠40只，随机分为对照组和照射组，每组20只。照射组大鼠采用¹³⁷Cs γ射线照射，吸收剂量率为0.353 mGy/min，每天累积照射0.083 3 Gy，每3天累积剂量为0.25 Gy；对照组大鼠不作任何处理。分别于照射前1 d和照射开始后第3、6、9、12 d收集大鼠尿液，对照组与照射组开始照射后第6 d同步收集尿样。采用核磁共振技术对大鼠尿样进行检测，结合主成分分析法和偏最小二乘法判别法，分析对照组与各剂量组大鼠尿液中小分子代谢物的差异。结果 小剂量γ射线累积照射后，各剂量亚组大鼠尿液中小分子代谢物发生了变化，各剂量组共发现了5种共同差异代谢物，分别为糖类、瓜氨酸、牛磺酸、柠檬酸盐和尿嘧啶。4个剂量亚组大鼠尿中5种差异代谢物相对水平分别高于对照组（P<0.05）；其中牛磺酸相对水平与累积剂量呈正相关关系（P<0.05）。结论 小剂量γ射线累积照射可造成大鼠尿液中小分子代谢物扰动。

Effects of small dose accumulative γ-irradiation on the small molecular metabolites in rats urine

Objective To observe the effects of accumulative Cs-137(¹³⁷Cs) γ irradiation at small dose on small molecular metabolites in rats urine.Methods 40 specific pathogens free grade healthy male SD rats were divided into control group and irradiated group with 20 rats in each group. The irradiated group was irradiated by ¹³⁷Cs γ-ray at absorbed dose rate of 0.353 mGy/min. The accumulated dose of every day was 0.083 3 mGy. The control group was not irradiated. Urine of irradiated group was collected at first day before irradiation and 3 rd, 6 th, 9 th, 12 th day after radiation commence. Urine of control group was collected at 6th day after radiation commence. The accumulated doses were 0.00, 0.25, 0.50, 0.75, 1.00 Gy consequently. Urine of control group and irradiated group were collected at the same time. Techniques of 1H-NMR combined with principal components analysis (PCA) and partial least square discriminate analysis(PLS-DA) were used to compare the metabolite disparity of different groups.Results The results demonstrated obviously differences in urine metabolites after irradiation. There were five kind common different metabolites at different dose. They were carbohydrate, citruline, taurine, citric acid and uracil accordingly. The relative contents of five metabolites at different dose group were higher than those of the control group(P<0.05). The relative contents of taurine has the positive proportion with accumulated dose, the dose-effect relationship was ?=0.004-0.015x+0.058x²(R²0.8821).Conclusion There are some changes in small molecular metabolites about rats urine before and after small dose accumulative γ-irradiation.