Miró O, Casademont J, Grau J M, Jarreta D, Urbano-Márquez A, Cardellach F
Department of Internal Medicine, Hospital Clínic, Medical School, University of Barcelona, Catalonia, Spain.
Br J Rheumatol. 1998 Oct;37(10):1047-53.
Mitochondrial dysfunction in idiopathic inflammatory myopathies (IIM) remains a controversial issue. The aim of the present study was to investigate the correlation between histological abnormalities and the biochemical function of the skeletal muscle mitochondria from patients with dermatomyositis (DM).
We evaluated 10 patients with a new diagnosis of DM and 15 healthy individuals, matched by age and gender. Muscle biopsy was routinely processed for histochemical studies and biochemical analysis of pure mitochondria. The percentages of ragged-red fibres (RRF), cytochrome c oxidase (COX)-negative fibres and succinic dehydrogenase (SDH) hyper-reactive fibres were calculated, oxygen utilization using different substrates was assessed polarographically, and enzymatic activity of individual complexes of the electron transport chain (ETC) and ATPase was measured spectrophotometrically.
We found an increased percentage of COX-negative and SDH hyper-reactive fibres in DM patients (0.82 and 1.82%, respectively) compared to controls (0.26 and 0.22%; P < 0.05 and P = 0.001, respectively); however, oxidation rates of different substrates and enzymatic activities of ETC and ATPase did not differ significantly between both groups.
The overall function of ETC from skeletal muscle mitochondria is not affected in DM.
特发性炎性肌病（IIM）中的线粒体功能障碍仍是一个有争议的问题。本研究的目的是探讨皮肌炎（DM）患者骨骼肌线粒体的组织学异常与生化功能之间的相关性。
我们评估了10例新诊断为DM的患者和15名年龄及性别相匹配的健康个体。肌肉活检常规进行组织化学研究和纯线粒体的生化分析。计算破碎红纤维（RRF）、细胞色素c氧化酶（COX）阴性纤维和琥珀酸脱氢酶（SDH）高反应性纤维的百分比，用极谱法评估不同底物的氧利用情况，并用分光光度法测量电子传递链（ETC）和ATP酶各个复合物的酶活性。
我们发现，与对照组相比，DM患者中COX阴性纤维和SDH高反应性纤维的百分比增加（分别为0.82%和1.82%）（对照组分别为0.26%和0.22%；P分别<0.05和P = 0.001）；然而，两组之间不同底物的氧化速率以及ETC和ATP酶的酶活性没有显著差异。
DM患者骨骼肌线粒体ETC的整体功能未受影响。
