Ohkoshi N, Mizusawa H, Shiraiwa N, Shoji S, Harada K, Yoshizawa K
Department of Neurology, University of Tsukuba, Ibaraki, Japan.
Muscle Nerve. 1995 Nov;18(11):1265-71. doi: 10.1002/mus.880181108.
Immunohistochemical analyses were made of the superoxide dismutases (Mn-SOD and Cu/Zn-SOD) in biopsied muscles from 7 patients with mitochondrial encephalomyopathies that included mitochondrial encephalomyopathy, lactic acidosis and strokelike episodes (MELAS), and chronic progressive external ophthalmoplegia (CPEO). Mn-SOD mainly was present in the subsarcolemmal region, but it also was found in a coarsely granular, reticular, or diffuse pattern of staining within the muscle fibers. These Mn-SOD-positive fibers corresponded almost completely to the ragged-red fibers. The immunoreaction for Cu/Zn-SOD was weakly positive in some of the muscle fibers positive for Mn-SOD. In CPEO, Mn-SOD-positive fibers predominantly showed decreased cytochrome c oxidase (COX) activity. In MELAS, Mn-SOD-positive fibers tended to be stained deeply for COX although a few were COX-negative. These findings suggest that Mn-SOD-positive fibers can be used to make a differential diagnosis between CPEO and MELAS and that in mitochondrial encephalomyopathies Mn-SOD in the ragged-red fibers may protect against oxidative stress.
对7例线粒体脑肌病患者的活检肌肉进行了超氧化物歧化酶（锰超氧化物歧化酶和铜/锌超氧化物歧化酶）的免疫组织化学分析，这些患者包括线粒体脑肌病伴乳酸酸中毒和卒中样发作（MELAS）以及慢性进行性眼外肌麻痹（CPEO）。锰超氧化物歧化酶主要存在于肌膜下区域，但也在肌纤维内以粗颗粒状、网状或弥漫性染色模式被发现。这些锰超氧化物歧化酶阳性纤维几乎完全对应于破碎红纤维。在一些锰超氧化物歧化酶阳性的肌纤维中，铜/锌超氧化物歧化酶的免疫反应呈弱阳性。在CPEO中，锰超氧化物歧化酶阳性纤维主要显示细胞色素c氧化酶（COX）活性降低。在MELAS中，锰超氧化物歧化酶阳性纤维尽管有少数为COX阴性，但往往COX染色较深。这些发现表明，锰超氧化物歧化酶阳性纤维可用于CPEO和MELAS的鉴别诊断，并且在线粒体脑肌病中，破碎红纤维中的锰超氧化物歧化酶可能抵御氧化应激。
