Pregnancy-Induced Amelioration of @entity3986 Phenotype in mdx XXXX via Muscle Membrane Stabilization Effect of Glucocorticoid.

@entity62817 @entity1420 @entity19 @entity1457 @entity1112 @entity3986 @entity53 @entity2819 @entity1555 @entity2100 @entity617
UNASSIGNED: @entity1555 ( @entity1555 ), the most common and severe type of dystrophinopathy, is an @entity1112 caused by the absence of dystrophin, which leads to @entity2100 and vulnerability of the sarcolemma to mechanical stretching with increased membrane permeability. Currently, glucocorticoids such as @entity617 are the only medication available for @entity1555 . However, molecular pathways responsible for this effect are still unclear. In addition, it remains unclear whether sex-related factors, including pregnancy and the postpartum period, affect the phenotype of dystrophinopathy. Here, we report the amelioration of muscle membrane permeability in the diaphragm muscle of pregnant and postpartum, but not in nulliparous, mdx @entity19 , an animal model for @entity1555 , during the physiological surge of @entity2819 , the most abundant glucocorticoid in rodents. Cultures of single muscle fibers and myotubes isolated from mdx @entity19 diaphragm demonstrate resistance to @entity1457 when treated with @entity2819 but not with @entity53 or @entity1420 . This @entity2819 -mediated resistance was diminished by an antagonist of @entity2819 , indicating that the glucocorticoid-glucocorticoid receptor axis plays a role in this membrane stabilization effect on muscle. Moreover, subcutaneous injection of @entity2819 into mdx @entity19 showed decreased membrane permeability. This is the first report to demonstrate that pregnancy-related resistance to muscle fiber damage in mdx @entity19 due to the membrane stabilization effect of @entity2819 . We also propose that this membrane stabilization effect is exerted through @entity62817 up-regulation as the molecular mechanisms of glucocorticoid effects on @entity1555 muscle. Furthermore, single muscle fiber culture studies provide a sensitive chemical screening platform for @entity3986 .
