EFFECT OF TRANSFECTION WITH SUPEROXIDE-DISMUTASE EXPRESSION PLASMID ON SUPEROXIDE ANION-INDUCED CYTOTOXICITY IN CULTURED RAT LUNG-CELLS

Human Cu, Zn-superoxide dismutase (hSOD) cDNA Has inserted into a euka ryotic expression plasmid (pRc/CMV) under the control of a cytomegalov irus promoter, The hSOD expression plasmid (pRc/CMV-SOD) was transfect ed into L2 cells by means of lipofection, The integration of the hSOD gene in genomic DNAs in the cells transfected with pRc/CMV-SOD plasmid was examined by Southern blotting using hSOD cDNA as the probe, Howev er, Southern blots of host cells (without transfection) and CMV cells (pRc/CMV plasmid transfection) indicated no hybridization of hSOD cDNA . Western blots indicated that hSOD was expressed in CMV-SOD cells, Th e SOD activity in CMV-SOD cells was about twice that in host and CMV c ells. Furthermore. this SOD activity. in CMV-SOD cells was enhanced fo r 60 d after the selection of cell clones,After exposure to paraquat a nd catalase., about 90% of the CR IV-SOD cells survived compared with the untreated controls, whereas about 60% of the host cells survived, The production of lipid peroxidation in host cells increased significa ntly after exposure to both paraquat and catalase, whereas that in CMV -SOD cells did not change. The correlation between the surviving cells and lipid peroxidation was inverse, These results indicated that tran sfection with the SOD gene was effective against superoxide anion indu ced cvtotoxcity.