The effects of glucocorticoid and voluntary exercise treatment on the development of thoracolumbar kyphosis in dystrophin-Deficient Mice

Abstract

The development of spinal curvature deformities is a hallmark of muscular dystrophy. While glucocorticoid treatment has been shown to prolong muscle function in dystrophic mice, its effects on the development of dystrophinopathic spinal deformation are poorly understood. In this study, we test the effects of glucocorticoid treatment on the onset of thoracolumbar kyphosis in the dystrophin-deficient mdx mouse using voluntary running exercise to exacerbate muscle fibrosis. We measure the kyphotic index, erector spinae muscle fibrosis, and vertebral bone histomorphometry in 4-month-old mdx mice in four groups: sedentary control, exercise treated (continuous voluntary access to an activity wheel), glucocorticoid-treated, and glucocorticoid + exercisetreated. Exercise treated mice were found to have significantly lower kyphotic index (i.e., greater kyphosis) and greater muscle fibrosis relative to controls (p.