镉引起蚕豆(Vicia faba)叶片DNA损伤和细胞凋亡研究

以蚕豆为研究对象,采用碱性、半碱性和中性彗星实验方法研究Cd对植物DNA的损伤,同时还采用DAPI染色法从细胞形态学入手研究Cd诱导的蚕豆叶片的细胞凋亡.用3种彗星实验研究Cd处理蚕豆叶片DNA损伤,结果表明Cd能够引起蚕豆叶片DNA损伤,但是不同Cd浓度引起DNA损伤的种类不同:5mg·L^-1Cd处理主要引起单链DNA损伤和碱性不稳定位点的形成;10mg·L^-1Cd处理时开始检测到DNA双链断裂;20mg·L^-1Cd处理下,各种类型的DNA损伤均明显增加,且DNA双链断裂尤其明显.DAPI染色法通过细胞形态学变化来检测蚕豆叶片细胞凋亡的结果表明,蚕豆叶片细胞在Cd处理下发生凋亡的过程与DNA损伤过程有很大的相关性.结果表明,Cd是一种基因毒性物质,同时证明Cd引起的DNA损伤是引起细胞发生凋亡的机制之一.

DNA Damages and Apoptosis Induced by Cd in the Leaves of Horsebean Vicia faba

DNA damages and programmed cell death in leaves of Vicia faba induced by Cd were studied with methods including alkaline/alkaline,alkaline/ neutral,neutral/neutral comet assay and DAPI staining.Types of DNA damages induced by Cd were different detected by three types of comet assay.Single strand breakage and alkali labile sites were detected in the leaves of Vicia faba with 5mg·L^-1 Cd treatment by alkaline/alkaline comet assay.With 10mg·L^-1 Cd treatments,double strand breakages began to be detected by neutral/neutral comet assay.However,single strand breakages and alkali labile sites were still the main types of DNA damages.Three types of DNA damages increased significantly with 20mg·L^-1 Cd treatment especially double strand breakages.These results indicated that DNA damages increased with increasing of Cd concentration,which was consistent with the programmed cell death induced by Cd.The result of apoptosis detected by DAPI staining indicated that there existed a relationship between apoptosis and DNA damage.These results indicated that Cd was an element with high genotoxicity and DNA damage was one of the mechanisms of cell apoptosis induced by Cd.