The Relationship Between Amyotrophic Lateral Sclerosis And Mitochondrial Disfunction

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease,the upper and lower motor neurons simultaneously involved. The exact mechanism yet, unknown. Skeletal muscle is the effector innervated by motor nerve, if motor neuron damaged, skeletal muscle have characteristic pathological changes. In this paper we used the methods of muscle biopsy, histochemical and enzyme staining, pathological analysis and transmission electron microscopy observation. Study ALS patients in the clinical and pathological, discuss the pathogenesis of ALS from another perspective has opened up a new avenue.The objective of this reseach was to investigate the features of the clinical and pathological in amyotrophic lateral sclerosis and the relation between ALS and mitochondrial dysfunction. We chose 33 cases(16 cases from the University of Kagoshima, Japan, 13 cases from Hebei University Third Hospital and 5 cases from JiLin University First Hospital) consistented with the diagnostic criteria of ALS developed by the Chinese Medical Association neuropathy institution in 2001. All patients have had skeletal muscle open biopsy; muscle biopsy specimens rapidly placed on saturated saline gauze and placed in ice box; Fast Isopentane / liquid nitrogen frozen; Serial cryostat section(7μm) of fresh frozen tissue were stained with the following chemical and enzymatic stains : hematoxylin–eosin, modified gomori trichrome, cytochrome C oxidase, succinate dehydrogenase, and nicotinamide adenine dinucleotide-tetrazolium reductase, adenosine triphosphate (pH:4.35,4.65,9.83) staining; Transmission electron microscopy of biological sample preparation; microscopy and transmission electron microscopy observation, the pathologic analysis.The experiment analysised of 33 cases of ALS patients, 23 were male and 10 were female. With ages ranged from 37-75 years old, the average age was 55.3.The time from fell ill to biopsy was between 0.5 to 7 years. 5 cases (15.1%) were began from brainstem; 12 cases (36.4%) were began from lower limb and15 cases (45.5%) were began from upper limb; only one(3%) began from four limbs. Lower motor neuron involvement (hand's small muscle atrophy, weakness, muscle fibrillation, the weakening or disappearance of tendon reflexes) accounted for 93.9%; upper motor neuron involvement (upper and lower limb spastic paralysis, hypermyotonia, tendon hyperreflexia, myoclonus, Hoffmann sign and Babinski sign positive) accounted for 84.4%; brainstem involvement (dysarthria, acataposis, choking water) accounted for 33.3%, both upper and lower motor neuron simultaneously involved accounted for 78.1%, the patients who involved only upper or lower motor neurons may because the short cause of disease. Electromyogram (EMG) : neurogenic changed 93.2%; myogenic changed 3.4% myogenic and neurogenic changed in both 3.4%. Creatine kinase normal 75%, mild-to-moderate increased 25%. One with temperament changed, considered had cortex degeneration lesions simultaneous.Pathology analysis: 1.The characteristics expressions of histochemical stains: the muscle fibers'diameter were between 4-150 microns. 63.6% of muscle fiber degeneration,48.5% of the pyknotic nuclear clumps phenomenon, 12.1% of ragged-red fiber(RRF), 57.6% of small angular fibers, 93.9% of group atrophies, 60.6% of fiber type grouping. 2.The characteristic expressions of enzymology stains:①mitochondria aggregation were showed under the sarcolemma in SDH, NADH-TR and CCO stain;②the activity of oxidation enzyme were abnormal: CCO partly or completely defect were 43.75%, the activity of enzyme increased were 9.4%, both the activity of enzyme deficient and increased have accounted for 6.25%; the activity of SDH and NADH-TR enzyme abnormal were for 43.3% and 59.4%. 3. Ultrastructural features: mitochondrial decrease and pyknosis mitochondria were seen under the sarcolemma. Filamentous bodies, glycogen and lipofuscin granules were in regions. Sarcoplasmic inocomma structure was unclear, Z lines was mildly disorder, the thick and thin myofilaments ranked disorder, was homogeneous.Myofilament partial dissolve, cytoplasmic matrix partial cavitation.In sum, we came to the conclusion: 1. It was difficult to make clinical diagnosis for the ALS patients in early period, but pathology biopsy revealed a unique advantage. There were 33 patients in this study, including 6 cases with less than a year's course of disease have had muscle biopsy and all of them had characteristic pathologic changes. So for the early suspicious cases, it was advocated to do muscle biopsy, pathologic analysis and diagnosis. 2. RRF, mitochondria aggregation under the sarcolemma and the pathological characteristic expressions of enzymology stains supported mitochondrial dysfunction existed in ALS. RRF and mitochondria aggregation under the sarcolemma emerged in muscle pathology suggested that mitochondria accumulation in muscle fibers and mitochondrial dysfunction meaned that muscle fibers mitochondrial oxidative metabolism disorder; CCO, SDH and NADH-TR were the key enzyme of mitochondrial respiratory enzymes in cell oxidation process. The enzymatic changes existed in ALS muscle fibers also demonstrated that ALS had mitochondrial dysfunction. 3. Electron microscopy showed mitochondrial decrease and pyknosis mitochondria were seen under the sarcolemma. Suggest that mitochondrial dysfunction, which may be related with apoptosis were exist in ALS.The mitochondria in skeletal muscle was decrease and pyknosis by electron microscopy in our research, and enlarged mitochondria, cristae ranked disoreder, vacuolus appeared were reported in the other literature. Mitochondria decrease and pyknosis were the performance of late degenerative disease, which may be related with apoptosis. Put clues for further study of the relationship between ALS, mitochondrial dysfunction and apoptosis, and opened up a new channel to discuss the pathogenesis of ALS.