The Quantitative Study On Muscular Fiber Type In Duchenne Muscular Dystrophy

Duchenne Mucular Dystrophy is one of the recessive geneticdisorders by X linkaged in neuromuscular system. DMD is the mostcommon and severe Muscular dystrophy in children. Diagnose on DMD depends on clinical symptoms, history offamilial inheritance, enzymology alteration, electromyogram andmuscular biopsy. There is no effective treatment at present. Skeletal muscular biopsies of fifteen cases of DMD wereinvestigated. After being rapidly frozen, the samples were made intofrozen sections which were then subjected to myofibril HE, MGT,PAS, NADH-TR, ACP, ANAE, SDH and ATP ase stain. ATP ase stainwas carried out through three different PH conditions. After we typedand marked, the images were imput to CIAS image analysis systemand the fiber traverse area, circumference length, diameter ofequivalent circle, maximal and minimal diameters were determined ineach type of DMD. We contrasted the different result at the same time.The skeletal muscles of six cases of normal children were used ascontrol group. The results were showed that: the sizes of muscular fibers wereuneven and diffused distribution. Auantic muscle fibers were littleround. The muscle sleeve and muscle bundle coat increased. Themuscle fibers were hyaloid degeneration, cellular necrosis, muscularenglobement through HE and MGT ase stain. A section of musclefibers were granular and coarse stain through NADH-TR and SDH asestain. Necrotic muscle fibers were red stain through ACP ase stain.The staining intensities on different muscle fiber types can beclassified in four grades: black, grey, grayish and white. The changesof parameters of DMD were very different from those of the controlgroup. The results possessed statistical significance. The parameters offiber traverse area, circumference length, diameter of equivalent circle,maximal an minimal diameters in DMD were different from controlgroup significantly (P<0.05). The average values of each parameter asthe surface area, circumference, equivalent circle diameter, maximaland minimal diameters were higher than those of the normal controlgroup. A comparison of equivalent circle diameters between differentmuscle fiber types showed that it was greater in fiber typeâ…  than thatin type â…¡ A. A determination on the distribution pattern of differentmuscle fiber types showed a basically equal distribution of the 2 types(P>0.05).We found out that the size of muscle fibers were uneven andauantic muscle fibers were little round. The muscle fibers weremyofibrosis, cellular necrosis and muscular englobement throughcreatase histochemical stain. Type â…  and â…¡ muscle fibers weredamaged, type â…¡B muscle fibers reduced and type â…¡C muscle fibersgreat increased by computer analysis. This characterization provides areliable theoretical basis for distinguishing from other type disease.