Muscle pathology and electron microscopy characteristics of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes / 中风与神经疾病杂志

ABSTRACT

@#Objective　To investigate the muscle pathology and electron microscopy characteristics of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode.Methods　Muscle pathology and electron microscopy data from 33 cases of MELAS syndrome confirmed by muscle pathology and gene sequencing in the Fifth Affiliated Hospital of Zhengzhou University and the First Affiliated Hospital of Zhengzhou University from January 2013 to January 2019 were collected and analyzed retrospectively.Results　RRF were found in 25 cases under the light microscope by modified Gomori staining.Ragged-blue fibers (RBF) were found in 28 cases by SDH staining,and the activity of oxidase was increased.In 26 cases,the arterial walls of intermuscular arterioles were strongly SDH-reactive,suggesting SSV phenomenon,in which 2 cases RBF and RRF were not seen.The activity of oxidase was disappeared or decreased in 22 cases by COX staining,indicating COX negative muscle fiber.Fifty patients were examined by electron microscopy,the number and structural abnormalities of mitochondria were observed.Besides,the crystalline inclusion bodies in mitochondria were arranged in a “parking lot” pattern.Conclusion　RRF,SSV phenomenon and negative muscle fiber by COX staining were the main pathological changes of muscle in MELAS syndrome.The inclusion of the crystalline inclusions in the mitochondria was a “parking lot” arrangement,which was a typical change in the electron microscope of MELAS syndrome.These characteristics were very important for the diagnosis of MELAS syndrome.