EFFECT OF TRANSFECTION WITH A SUPEROXIDE-DISMUTASE EXPRESSION PLASMIDON XANTHINE XANTHINE OXIDASE-INDUCED CYTOTOXICITY IN CULTURED RAT LUNG-CELLS/

We inserted human Cu, Zn-superoxide dismutase (hSOD) cDNA into the euk aryotic expression plasmid (pRc/CMV) under the control of the cytomega lovirus promoter. The hSOD expression plasmid (pRc/CMV-SOD) was transf ected in L2 cells by mean of lipofection. The intracellular SOD activi ty in pRc/CMV-SOD transfect cells (CMV-SOD cells) was about twice that in host cells. However the level of extracellular SOD activity was si milar in CR?V-SOD and host cells, When exposed to xanthine (X)/xanthin e oxidase (XO) to generate active oxygen species, significantly more C MV-SOD cells than host cells survived, The production of lipid peroxid ation in host cells significantly increased in the presence of X/XO, b ut that in CMV-SOD cells did not change, Thus, transfection with SOD g ent effectively prevented X/XO-induced cytotoxicity. The results indic ated that increasing tile level of intracellular SOD activity protecte d cells against extracellular superoxide anion stress.