Freeze‐fracture electronmicroscopic analysis of plasma membranes of cultured muscle cells in Duchenne dystrophy

Depletion of intramembranous particles has been reported in the muscle fiber plasma membrane in Duchenne dystrophy. We searched for a similar abnormality in plasma membranes of cultured muscle cells obtained from six patients with Duchenne dystrophy and six controls. A precise method for phase microscopic to freeze-fracture electronmicroscopic correlation was devised to identify the cell of origin of each replicated membrane face. For both control and patient cells, P-face particle density was higher in myotubes than in mononuclear cells. However, there were no significant differences between control and dystrophic cells when comparing P faces of myotubes, E faces of myotubes, P faces of single cells, or E faces of single cells. The frequency distribution of particle diameters was similar in P faces of control and Duchenne myotubes. Other structural features of the freeze-fractured plasma membrane also were similar.