线粒体脑肌病临床病理及部分基因突变研究

THE STUDY OF PATHOLOGY AND GENE MUTATION IN PATIENTS WITH MITOCHONDRIAL ENCEPHALOMYOPATHY

目的探讨线粒体脑肌病患者骨骼肌组织病理特点及线粒体DNA(mitochondrial DNA,mtDNA)在3243、8344和8993位点的点突变,为疾病的诊断和鉴别诊断提供依据。方法取8例患者及10例对照者骨骼肌活检标本速冻后切片,常规和酶组化学染色,光镜下观察其病理特点,并提取骨骼肌中的总DNA,以相应的引物行PCR扩增,分别应用Bgl Ⅰ、ApaI、Sma Ⅰ和Msp Ⅰ酶酶切后,琼脂糖电泳判定,检测mtDNA中3243、8344和8993位点是否存在基因突变。结果 8例患者的肌肉病理均存在不整边红纤维;其中2例患者肌肉中mtDNA存在A3243G点突变,1例存在A8344G点突变,8例患者均未发现T8993G和T8993C突变。结论肌肉组织病理学方法和分子生物学研究可以为线粒体脑肌病的诊断和鉴别诊断提供依据。

Objective To investigate the histopathologic features of skeletal muscle and the point mutation at nt3243, nt8344 and nt8993 of mitochondrial DNA （mtDNA） in patients with mitochondrial eneephalomyopathy. Methods Serially sectioned frozen skeletal muscle specimens from 8 patients and 10 controls with a battery of histochemical stains were reviewed under light microscope. Total DNA was extracted from the muscle specimens and amplified by PCR method using corresponding oligonueleotide primers. The DNA fragments were digested with the restriction enzyme Bgl I , ApaI, Sma I and Msp I , then the digested DNA fragments were analyzed with eleetrophoresed method. Results The histopathologic findings of ragged red fibers （RRF） existed in skeletal muscle specimens from 8 patients. The muscle mtDNA A3243G point mutation was identified in two cases and the mtDNA A8344G point mutation was identified in one case with mitoehondrial myopathy. The mtDNA T8993G and T8993C point mutations were not observed in all of the cases. Conclusion The muscle histopathologic method and molecular biological study are useful for the diagnosis and differential diagnosis of mitochondrial encephalomyopathy.