Correlative study of the incidence of opaque, necrotic and regenerative fibers in Duchenne dystrophy.

We studied the incidence of opaque, necrotic, and regenerative muscle fibers (OFs, NFs, RFs) in muscle biopsies from 21 patients, aged 8 months to 24 years, with Duchenne muscular dystrophy (DMD). OFs varied from case to case with an average rate of 8.3%. NFs and RFs were high in younger patients and decreased with age. The incidence of OFs, NFs, and RFs correlated to patient age with these coefficients: r = -0.38, -0.91, and -0.86. Except for OFs, all correlations were significant (p less than 0.001). There was no significant correlation between the incidence of OFs and NFs in each case of DMD. Considering the results of previous biochemical analysis of single OFs, we suggest that OFs may comprise two types of muscle fibers: (1) pathological muscle fibers to be regarded as precursors of NFs, and (2) muscle fibers undergoing artificial changes.