Oliver P D, Newsome D A
Sensory and Electrophysiology Research Unit, Touro Infirmary, New Orleans, LA 70115.
Invest Ophthalmol Vis Sci. 1992 May;33(6):1909-18.
Human retinal pigment epithelium (RPE) contains two genetically distinct forms of superoxide dismutase (SOD) enzymes that scavenge harmful superoxide anions. Biochemical and immunochemical techniques were used to compare levels of copper-zinc- and manganese-containing forms of SOD (CuZn-SOD and Mn-SOD) in human adult and fetal RPE cells. It was found that Mn-SOD activity was higher in adult than fetal RPE cells, both in vivo and in vitro. Immunolocalization of Mn-SOD in cultured RPE cells showed a greater reactivity in the mitochondria of the adult cells. Primary cultures of adult RPE contained cells with various patterns of mitochondria as shown by immunolabeling for Mn-SOD. Adult RPE cells were more resistant to the effects of a superoxide generator, paraquat, which appeared to disrupt mitochondrial integrity as judged by staining with rhodamine 123. These results suggest that high levels of Mn-SOD protect mitochondria from oxidative damage that probably occurs with aging in the RPE.
人视网膜色素上皮（RPE）含有两种基因不同形式的超氧化物歧化酶（SOD），可清除有害的超氧阴离子。采用生化和免疫化学技术比较成人和胎儿RPE细胞中含铜锌和含锰形式的SOD（CuZn-SOD和Mn-SOD）水平。结果发现，无论在体内还是体外，成人RPE细胞中的Mn-SOD活性均高于胎儿RPE细胞。培养的RPE细胞中Mn-SOD的免疫定位显示，成人细胞线粒体中的反应性更强。成人RPE的原代培养物中含有具有不同线粒体模式的细胞，这通过对Mn-SOD的免疫标记得以显示。成人RPE细胞对超氧化物产生剂百草枯的作用更具抗性，用罗丹明123染色判断，百草枯似乎会破坏线粒体的完整性。这些结果表明，高水平的Mn-SOD可保护线粒体免受RPE中可能随衰老而发生的氧化损伤。
