Time course of changes in plasma membrane permeability in the dystrophin‐deficient mdx mouse

Abstract

Control C57BI/10 and mutant, dystrophin‐deficient mdx mice of different ages were used to study the permeability of the plasma membrane to cytosolic components, to a vital stain (procion orange) and to extra‐cellular ₄₅calcium. Prenecrotic, 14 ± 2‐day‐old mdx mice had normal serum activities of creatine kinase (CK) and pyruvate kinase (PK). Muscles from these animals also had no increased permeability to procion orange or extracellular ₄₅calcium. Serum activities of CK and PK had risen acutely in the 21‐day‐old mdx mouse compared with control and remained elevated up to 6 months of age. The influx of procion orange and ₄₅calcium content were abnormally elevated in the 40 ± 4‐day‐old mdx mouse. These data provide no evidence for an increase in muscle plasma membrane permeability as a primary pathogenic effect of a lack of dystrophin, but results suggest that some factor expressed or deexpressed during mouse development may be necessary for the full expression of the dystrophic process. © 1994 John Wiley & Sons, Inc.