Lai M T, Ohmichi T, Ogawa T, Nishizaki K, Masuda Y
Department of Otolaryngology, Okayama University Medical School, Shikata-Cho, Japan.
Acta Otolaryngol. 1997 May;117(3):437-46. doi: 10.3109/00016489709113418.
The immunohistochemical method and electron spin resonance (ESR) spin trapping assay were employed to detect the localization and biochemical activity of superoxide dismutases (SODs) in the rat nasal mucosa. Manganese SOD and copper-zinc SOD were immunohistochemically illustrated to be richly expressed in the epithelial cells and the subepithelial glands of nasal mucosa. The olfactory vesicles also showed positive immunostaining for manganese SOD and copper-zinc SOD. ESR spin trapping assay revealed that SOD activity in the mucosa of olfactory areas was significantly higher than in the mucosa of respiratory areas; however, the ratio of SOD activity in the mitochondrial fraction to SOD activity in the cytosolic fraction was similar, approximating 17:83 in the mucosa of both the olfactory and respiratory areas. The predominant localization of SODs in epithelial cells of nasal mucosa suggests the importance of mucosal epithelium in protecting nasal mucosa against cytotoxic superoxide (O2-) radicals. Epithelial goblet cells and the connective tissue of lamina propria, which showed no positive immunostaining for SODs, are considered to be vulnerable to oxidative insults implicated in the generation of O2- radicals. The higher SODs activity in the mucosa of olfactory areas implies that there is a different requirement of SOD in mucosa of the respiratory and olfactory areas on scavenging microenvironmental O2- radicals.
采用免疫组织化学方法和电子自旋共振（ESR）自旋捕获分析法检测大鼠鼻黏膜中超氧化物歧化酶（SOD）的定位和生化活性。免疫组织化学显示，锰超氧化物歧化酶和铜锌超氧化物歧化酶在鼻黏膜的上皮细胞和上皮下腺体中大量表达。嗅泡对锰超氧化物歧化酶和铜锌超氧化物歧化酶也呈阳性免疫染色。ESR自旋捕获分析表明，嗅觉区黏膜中的SOD活性显著高于呼吸区黏膜；然而，线粒体部分的SOD活性与胞质部分的SOD活性之比相似，在嗅觉区和呼吸区黏膜中均约为17:83。SOD在鼻黏膜上皮细胞中的主要定位表明黏膜上皮在保护鼻黏膜免受细胞毒性超氧阴离子（O2-）自由基侵害方面的重要性。对SOD无阳性免疫染色的上皮杯状细胞和固有层结缔组织被认为易受与O2-自由基产生相关的氧化损伤。嗅觉区黏膜中较高的SOD活性意味着呼吸区和嗅觉区黏膜在清除微环境O2-自由基方面对SOD有不同需求。
