金属毒性研究(Ⅱ)

Approach of metal cytotoxicity(Ⅱ)

利用细胞生物学技术从定量和定性两个方面探讨了Cr(Ⅲ ) ,Cr(Ⅵ ) ,Ni,Al,Ag和V金属离子对生命组织的毒性作用。研究中发现 ,Cr(Ⅵ )对细胞DNA ,RNA合成限制最为显著 ,Ni和V金属离子在同等水平上妨碍RNA合成 ,随着离子浓度增加 ,Cr(Ⅲ )离子对细胞DNA及RNA限制增大。Al离子对RNA合成限制大于对DNA合成。Ag离子对细胞DNA ,RNA合成限制作用相同。细胞谷胱甘肽 (GSH)还原能力强 ,是细胞最重要的解毒物质 ,也是细胞中防御毒性物质最关键的物质。细胞GSH还原能力定量分析表明 :微量的Cr(Ⅵ )即可导致细胞GSH下降。金属Ni离子破坏细胞骨架 ,使细胞内信息传递受阻 ,亦表现较强毒性。

By use of cellular biological techniques, the poison mechanism of metal ions (Cr(Ⅵ), Ni, V, Cr(Ⅲ), Ag, and Al) on living tissue was both quantitatively and qualitatively approached. The results show that Cr(Ⅵ) has a notable action on cellular both DNA and RNA synthetic functions. With increasing concentration, the limit action of Cr(Ⅲ), on DNA, RNA synthetic abilities increases. Different to other five metal ions, the limit of Al ion on RNA is greater than that of Al ion on DNA. The limitation of V, Ag ions on DNA is same to that of V, Ag ions on RNA. Glutathione is most important of detoxification in living cells. It is also the most important defensive. Trace Cr(Ⅵ), in culture medium results in the decreasing of GSH in living tissue. Similar to that, a little higher Ni ion concentration seriously reduces the GSH content in living tissue. It is suggested that Cr(Ⅵ), Ni should destroy and/or disturb the orientation of the microtubulin in cell skeleton. For other four metal ions, together with increasing the concentration in culture medium, the osmotic pressure increases. Consequently, more metal ions entered cell membrane, more GSH were lost in cell.