Progression of kyphosis in mdx mice

Laws, Nicola and Hoey, Andrew (2004) Progression of kyphosis in mdx mice. Journal of Applied Physiology, 97 (5). pp. 1970-1977. ISSN 8750-7587

Abstract

Spinal deformity in the form of kyphosis or kyphoscoliosis occurs in most patients with Duchenne muscular dystrophy (DMD), a fatal X-linked disorder caused by an absence of the subsarcolemmal protein dystrophin. Mdx mice, which also lack dystrophin, show thoracolumbar kyphosis that progresses with age. We hypothesize that paraspinal and respiratory muscle weakness and fibrosis are associated with the progression of spinal deformity in this mouse model, and similar to DMD patients there is evidence of altered thoracic conformation and area. We measured kyphosis in mdx and age-matched control mice by monthly radiographs and the application of a novel radiographic index, the kyphotic index, similar to that used in boys with DMD. Kyphotic index became significantly less in mdx at 9 mo of age (3.58 ± 0.12 compared with 4.27 ± 0.04 in the control strain; P ≤ 0.01), indicating more severe kyphosis, and remained less from 10 to 17 mo of age. Thoracic area in 17-mo-old mdx was reduced by 14% compared with control mice (P ≤ 0.05). Peak tetanic tension was significantly lower in mdx and fell 47% in old mdx latissimus dorsi muscles, 44% in intercostal strips, and 73% in diaphragm strips (P ≤ 0.05). Fibrosis of these muscles and the longissimus dorsi, measured by hydroxyproline analysis and histological grading of picrosirius red-stained sections, was greater in mdx (P < 0.05). We conclude that kyphotic index is a useful measure in mdx and other kyphotic mouse strains, and assessment of paralumbar and accessory respiratory muscles enhance understanding of spinal deformity in muscular dystrophy.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to paper due to publisher copyright restrictions. Please access full text at publisher website, via above URL or at http://jap.physiology.org/cgi/reprint/97/5/1970?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&author1=hoey&fulltext=kyphosis+&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT
Depositing User: Ms Debbie White
Faculty / Department / School: Historic - Faculty of Sciences - Department of Biological and Physical Sciences
Date Deposited: 11 Oct 2007 01:13
Last Modified: 02 Jul 2013 22:46
Uncontrolled Keywords: espiratory muscles; latissimus dorsi; intercostal muscles; kyphotic index; hydroxyproline
Fields of Research (FOR2008): 06 Biological Sciences > 0606 Physiology > 060699 Physiology not elsewhere classified
Identification Number or DOI: doi: 10.1152/japplphysiol.01357.2003
URI: http://eprints.usq.edu.au/id/eprint/2720

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