中文摘要：

采用MTT法、琼脂糖电泳以及测定细胞内抗氧化指标的方法研究融合型超氧化物歧化酶PTD—SOD对UVB照射引起的L-02细胞损伤的保护和修复作用．细胞存活实验表明，辐射时间为45min，SOD活力为1200U·mL^-1时，在PTD—SOD保护和恢复作用下的细胞存活率可达94．0％和82．5％，而野生型SOD作用下的细胞存活率仅为68．2％和54．1％，与正常对照组相近．琼脂糖电泳结果显示，PTD—SOD能有效降低辐射对L-02细胞DNA的损伤程度．酶法检测细胞内的抗氧化指标时发现，PTD—SOD能有效地提高细胞内SOD活性，同时检测到细胞内过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH—PX）活力的增加．相对野生型SOD，融合蛋白PTD—SOD对UVB辐射下L—02细胞的保护和恢复能力得到了显著的增强，具有作为防治UVB损伤药物的潜力．

英文摘要：

MTT assay, DNA fragmentations analysis as well as intracellular antioxidant study with commercial analytical kits were employed to investigate the protection and restoration bioactivities of fused superoxide dismutase PTD - SOD on L - 02 cells exposed to UVB. Dates showed that the survival rates were 94.0% and 82.5% respectively, in groups of 1 200 U · mL^-1 PTD -SOD as protective agent or restorative agent, when L - 02 cells had been exposed to UVB for 45 min. Comparatively, the survival rates of wild - type SOD groups were only 68.2% and 54.1%, which were similar to those of control groups. Result of agarose gel electrophoresis indicated that PTD - SOD was capable of alleviating DNA damage significantly. Changes of intracellular antioxidant indicators showed that PTD - SOD increased intracellular SOD activities. Meanwhile, the intracellular enzymatic activities of catalase （CAT） and glutathione pemxidase （GSH- PX） showed remarkable increase. Compared with wild - type SOD, the bioactivities of fusion protein PTD- SOD in protectione and restoration on L- 02 cells against UVB radiation injury has been significantly enhanced. The fusion protein has hold tremendous potential as medicament in the field of prevention and treatment against UVB damage.