The membrane sealant poloxamer reduces membrane permeability in tibialis anterior muscles from dystrophic mdx mice

Duchenne muscular dystrophy is characterised by the loss of the membrane stabilizing protein dystrophin, resulting in an increased susceptibility to sarcolemmal injury. The membrane sealant Poloxamer 188 (P‐188) prevents sarcolemmal tearing in cardiac myocytes from dystrophic mdx mice. We tested the hypothesis that P‐188 would similarly reduce membrane tearing in skeletal muscles of mdx mice. Mdx and wild type mice were injected with Evans blue dye (EBD) an indicator of membrane permeability, then anesthetized for P‐188 (460mg/kg) or vehicle (200μL saline) infusion via the right jugular vein. The susceptibility of the tibialis anterior (TA) muscle to contraction‐induced injury (CI) was determined in situ and then prepared for histological quantification of EBD. TA muscles from mdx mice were more susceptible to CI than wild type mice, regardless of treatment. P‐188 decreased the proportion of EBD positive fibers by 53% in both uninjured and injured TA muscles from mdx mice (P<0.05). These findings indicate that while P‐188 does not alter the susceptibility to CI, it may play a role in maintaining sarcolemmal integrity in muscle fibers of mdx mice. Supported by the Muscular Dystrophy Association (USA).