维生素C对低硒高镉饲料饲养大鼠Ⅱ型肺泡上皮细胞DNA的影响

Effects of vitamin C on the DNA of type II alveolar epithelial cells of the rats fed with low selenium and high cadmium fodder

目的探讨维生素C对低硒高镉饲料饲养大鼠Ⅱ型肺泡上皮细胞(AT-Ⅱ)的影响。方法将72只Wistar大鼠随机分为8组(每组9只):普通饲料对照组(C1组),实验构成饲料对照组(C2组),低硒+高镉组(第1组),低硒+高镉+维生素C组(第2组),适量硒+高镉组(第3组),适量硒+高镉+维生素C组(第4组),高硒+高镉组(第5组),高硒+高镉+维生素C组(第6组)。采用单细胞凝胶电泳技术分别观察各组动物饲养14周后AT-Ⅱ细胞DNA的改变。结果大鼠AT-Ⅱ细胞DNA损伤率分别为:C1组9.00%,C2组9.20%,第1组34.20%,第2组18.60%,第3组19.00%,第4组14.40%,第5组13.80%,第6组9.40%。第6组大鼠AT-Ⅱ细胞DNA损伤率与C1组和C2组无显著差异(P均>0.05)。第4组和第5组AT-Ⅱ细胞DNA损伤程度较轻。第2组和第3组大鼠AT-Ⅱ细胞的DNA损伤较重。第1组大鼠肺细胞的DNA损伤最为严重(P<0.01)。结论低硒并高镉可在一定程度上改变AT-Ⅱ细胞的DNA生物学特性,维生素C可以对抗低硒并高镉对AT-Ⅱ细胞所致的这种变化。

Objective To elucidate the etiology of DNA impairment of type Ⅱ alveolar epithelial cells（AT-Ⅱ） of the rats fed with low selenium and high cadmium fodder,and the effect of Vitamin C. Methods With single cell gel electrophoresis technique, we observed the joint action of selenium, cadmium and vitamin C on DNA damage in AT-Ⅱ cells of the eight groups of rats fed separately with： normal（ 2 groups）, high Cd, high Cd ＋ high VC, low Se ＋ high Cd, low Se ＋ high Cd ＋ high VC, high Se ＋ high Cd and high Se ＋ high Cd ＋ high VC fodder for 14 weeks. Results Compared with the control, there was no DNA changes have been observed in the high Se ＋ high Cd ＋ high VC group. However, in the high Se ＋ high Cd group and high Cd ＋ high VC group, DNA damage of AT-Ⅱ cells could be detected clearly ;in the low Se ＋ high Cd ＋ high VC group and high Cd group, the degree of the DNA damage was more serious than the above two groups;in the low Se ＋ high Cd group, the extent of the DNA damage was the most serious in all of the groups be studied. Conclusion It is suggested that Se deficiency and simultaneously Cd overabundance may damaged DNA of AT-Ⅱ cells of the rats significantly, however, Vitamin C may protect AT-Ⅱ against the injury effectively.