三硝基甲苯致晶状体上皮细胞DNA损伤作用的研究

本文通过出生后７天和２４个月两组大鼠晶状体与２０％三硝基甲苯（ＴＮＴ）甘油：水（８：２）混悬液体外培养，培养箱通５％ＣＯ２，恒温３７℃，观察ＴＮＴ对晶状体上皮细胞ＤＮＡ的损伤程度，结果以反映单链ＤＮＡ断裂强度的Ｆ６３０／Ｆ５３０比值表示。ＨＰＬＣ分析发现经体外ＴＮＴ孵育的晶状体内含有ＴＮＴ及其代谢产物；当共同培养９６ｈ后，Ｆ６４０／Ｆ５３０比值随着ＴＮＴ剂量增加而增大，达到４０μＬ（１１．７４μｍｏｌ／Ｌ）时趋向平稳；当用ＴＮＴ浓度为４．４０μｍｏｌ／Ｌ的相同剂量培养时，４８小时后单链ＤＮＡ断裂最为严重Ｆ６３０／Ｆ５３０比值为１．５０，明显高子正常对照组（Ｐ＜０．０１）；幼鼠单链ＤＮＡ断裂程度显著高于老龄鼠（Ｐ＜０．０１）。

Study on Single Strand DNA Breaks of Lens Epithelial Cells Induced by 2,4,6-Trinitrotoluene and Its Metabolites

Lenses which were excised from both 7 days old and 24 months old rats were incubated at 37℃ with a mixture of 20% trinitrotoluene(TNT) dissolved in 80% glycerin in a 5% CO2/95% air incubator. The severe degree of single strand DNA breaks in lens epithelial cells was observed. Result were expressed in intensity of red fluorescence(F640) divided by green fluorescence(F530) from acridine orange in a single cell. As shown by HPLC analysis TNT could penetrate into lenses and in which some metabolites of TNT were produced.When lenses were incubated with variable doses of TNT were produced. When lenses were incubated with rariable doses of TNT for 96 hours, dose dependent degree of DNA strand breaks was obvious and became most severe after adding 4μL of 20% TNT(11. 74 μmol),and then the ratio of F640/F530 remained stable, as doses of TNT were further increased.When concentration of TNT in the medium was permanently maintained at 4.40 μmol, it is after 48 hours that the single strand DNA breaks of epithelial cells differed significantly from normal control(P<0.01). Ratio of f 640/F530 was 1. 5 Degree of the single strand DNA breaks in suckling rats was obviously higher than that of adult rats(P<0. 01).