目的 了解苯甲酸钠(Sodium benzoate,SB)是否存在低剂量兴奋效应(Hormesis)以及在低剂量兴奋效应带(Hormetic Zone)剂量范围的损害特性.方法 采用噻唑蓝(MTT)比色法、单细胞凝胶电泳(SCGE)和流式细胞术(FCM),观察经SB处理后的体外培养CHL细胞增殖率,判断是否存在Hormesis;观察SB处理后的体外培养CHL细胞DNA损害,细胞周期与凋亡率改变,判断在Hormetic Zone剂量范围的损害特性.结果 SB使体外培养CHL细胞增殖率增加,Hormetic Zone的剂量范围为0.514～666.667 mg/L,以111.111 mg/L的细胞增殖率最高,为空白对照组的104.58%;SB引起体外培养CHL细胞DNA损伤,19.531,78.125和156.25 mg/L 3个剂量组SCGE的细胞核尾长、尾长/头长、尾DNA%、Olive尾矩与空白对照组比较差别有统计学意义;SB在0.391～156.250 mg/L引起G0/G1期细胞数比例增加,而G2/M期和S期细胞数比例相应减少;SB在0.391～625.000 mg/L引起CHL细胞凋亡率均较空白对照组下降.结论 在该试验条件下,SB存在Hormesis,在Hormetic Zone剂量范围引起DNA损伤等生物学效应,对这种效应的利弊应审慎评价.

[Objective]To study whether there is hormesis effect by formaldehyde and the damage character under the dose of hormetic zone.[Methods]Chinese hamster lung fibroblast (CHL) cultured in vitro were used as experimental object,the effect on proliferation rate of CHL by formaldehyde at different doses was detected by MTT-test,the damage effect at the dose of hormetic zone was detected by single cell gel electrophoresis (SCGE) and western-blot test.[Results]After 24h treatment of formaldehyde,hormesis effect on proliferation rate of CHL was observed,the hormetic zone was 0.39 mg/L ~3.125 mg/L,and the proliferation rate of CHL at the dose of 3.125 mg/L was 105.98% of the blank control group. The evidence of the hormesis caused by formaldehyde was low-intermediate level. After 24h treatment of 0.196 mg/L ~12.500 mg/L formaldehyde in CHL,there were significant differences in nuclear tail length,tail length/head length,percentage of tail DNA and Olive tail moment among seven dosage groups (P0.05),and DNA damage was clearly observed at the dose of 1.563 mg/L. After 6h treatment of formaldehyde,the protein band of PARP-1 was pale and expression of PARP-1 with 116KD of relative molecular weight reduced at the dose of 0.781 mg/L,25 mg/L and 100 mg/L,and there was no significant difference in coloration of protein band between the dose group of 3.125 mg/L and the blank control group.[Conclusion]There is hormesis effect on proliferation rate of CHL by formaldehyde,and formaldehyde can cause DNA damage and reduce the protein expression of PARP-1 at dose of hormetic zone. The advantages and disadvantages of the effect should be evaluated prudently.

目的 研究甲醛、硫脲和硼砂在单独作用和加入小麦粉基质的情况下对蚕豆根尖微核率发生的影响.方法 将松滋青皮豆(Vicia faba)25℃恒温催芽根尖生长至2.5cm左右,根尖浸入受试液中处理6h,然后用双蒸水恢复24h,压片法制片,40倍镜下观察并记录各剂量组蚕豆根尖细胞微核率.结果 甲醛、硼砂和硫脲在一定剂量范围内可诱导蚕豆根尖微核率的升高,加入小麦粉与对受试物单独作用时微核率有差异.结论 3 种有害食品添加物对蚕豆根尖细胞有一定的遗传毒性.

[Objective]To study the micronucleus rate induced by Amaranth and Sunset Yellow in roottip cells of Vicia faba.[Methods] Micronucleus test was applied to assay the effect of Amaranth and Sunset Yellow at the doses about 2,1,1/2,1/4,1/8,1/16 times of the acceptable maximum level on micronucleus rates of root tip cells of Vicia faba,respectively.[Results]The micronucleus rates of Vicia faba increased at the dose range of 3.125～100 mg/L in Amaranth and of 6.25～200 mg/L in Sunset Yellow.[Conclusion]Amaranth and Sunset Yellow have a certain degree of genetic toxicity on Vicia faba root tip cells.