AIM To compare skeletal muscle mitochondrial enzyme activity and mitochondrial content between independently ambulatory children with cerebral palsy (CP) and typically developing children. METHOD Gracilis biopsies were obtained from 12 children during surgery (n=6/group, children with CP: one female, five males, mean age 13y 4mo, SD 5y 1mo, 4y 1mo-17y 10mo; typically developing children: three females, three males, mean age 16y 5mo, SD 1y 4mo, 14y 6mo-18y 2mo). Spectrophotometric enzymatic assays were used to evaluate the activity of mitochondrial electron transport chain complexes. Mitochondrial content was evaluated using citrate synthase assay, mitochondrial DNA copy number, and immunoblots for specific respiratory chain proteins. RESULTS Maximal enzyme activity was significantly (50-80%) lower in children with CP versus typically developing children, for complex I (11nmol/min/mg protein, standard error of the mean [SEM] 1.7 vs 20.7nmol/min/mg protein, SEM 4), complex II (6.9nmol/min/mg protein, SEM 1.2 vs 21nmol/min/mg protein, SEM 2.7), complex III (31.9nmol/min/mg protein, SEM 7.4 vs 72.7nmol/min/mg protein, SEM 7.2), and complex I+III (7.4nmol/min/mg protein, SEM 2.5 vs 31.8nmol/min/mg protein, SEM 9.3). Decreased electron transport chain activity was not the result of lower mitochondrial content. INTERPRETATION Skeletal muscle mitochondrial electron transport chain enzymatic activity but not mitochondrial content is reduced in independently ambulatory children with CP. Decreased mitochondrial oxidative capacity might explain reported increased energetics of movement and fatigue in ambulatory children with CP.

中文翻译：

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能走动的脑瘫儿童骨骼肌最大线粒体活性

目的比较独立行走的脑瘫（CP）儿童与正常发育儿童骨骼肌线粒体酶活性和线粒体含量。方法 手术期间从 12 名儿童（n=6/组，CP 儿童：1 名女性，5 名男性，平均年龄 13 岁 4 个月，SD 5 岁 1 个月，4 岁 1 个月-17 岁 10 个月；典型发育儿童：三名女性，三名男性，平均年龄 16 岁 5 个月，SD 1 岁 4 个月，14 岁 6 个月-18 岁 2 个月）。分光光度法酶促测定用于评估线粒体电子传递链复合物的活性。使用柠檬酸合酶测定、线粒体 DNA 拷贝数和特定呼吸链蛋白的免疫印迹评估线粒体含量。结果 对于复合物 I（11nmol/min/mg 蛋白质，平均值的标准误差 [SEM] 1.7 vs 20.7nmol/min/mg 蛋白质），CP 儿童的最大酶活性显着低于正常发育儿童（50-80%） , SEM 4), 复合物 II (6.9nmol/min/mg 蛋白质, SEM 1.2 vs 21nmol/min/mg 蛋白质, SEM 2.7), 复合物 III (31.9nmol/min/mg 蛋白质, SEM 7.4 vs 72.7nmol/min/mg蛋白质，SEM 7.2）和复合物 I+III（7.4nmol/min/mg 蛋白质，SEM 2.5 vs 31.8nmol/min/mg 蛋白质，SEM 9.3）。降低的电子传递链活性不是线粒体含量降低的结果。解释 独立行走的 CP 儿童的骨骼肌线粒体电子传递链酶活性降低，但线粒体含量不降低。