Increased resistance of the collagen in avian dystrophic muscle to collagenolytic attack: Evidence for increased crosslinking

Abstract

Fibrous collagen from normal (line 412) and dystrophic (line 413) chicken pectoral muscles was examined for susceptibility to bacterial collagenase by a pH-stat titration method to assess the kinetics of peptide bond hydrolysis. These experiments showed that there was a profound difference in the kinetics of hydrolysis using fibrous collagen purified from normal and dystrophic muscle. Although normal collagen was readily hydrolyzed by the collagenase, dystrophic collagen was not hydrolyzed in the presence of 200 microM Ca and was hydrolyzed slowly in the presence of 5 mM Ca. At this high Ca concentration, the Km for collagenase was six times higher in dystrophic collagen than in normal, whereas the maximum reaction rate (Vmax) remained the same. After CNBr digestion, peptides from both sources were readily hydrolyzed by collagenase in the presence of 200 microM Ca, and there was no noticeable difference in the reaction kinetics. The above results were not modified whether the chicken was sacrificed on day 4 or day 98 post-hatching, and the insusceptibility to collagenase preceded the clinical manifestations of dystrophy. The structure of both fibrous and CNBr-treated collagen from normal and dystrophic muscle was compared. One and two-dimensional gel electrophoreses showed identical peptide maps. Gel filtration of CNBr peptides showed in the excluded volume the presence of twice as much high-molecular-weight (presumably crosslinked) peptides from dystrophic collagen compared with normal. We conclude that the intermolecular crosslinks are more extensively formed in dystrophic collagen and that this increased crosslinking results in the increased resistance of the dystrophic collagen to collagenase.

Impact of prednisone on TGF‐β1 and collagen in diaphragm muscle from mdx mice

“…The increase of the mature HP cross-link observed in the diaphragm muscle from untreated mdx mice in this study is consistent with other previous studies. 11,12 Feit et al 11 observed an increase in collagen cross-linking in pectoralis muscle from dystrophic chickens. However, the specific gene or protein defect in the dystrophic chicken has not been identified.…”

“…The formation of the nonreducible HP cross-link alters the biophysical and biochemical properties of collagen leading to increased tensile strength 10,34 and increased resistance to proteolytic degradation. 5,11 It is unclear whether, and to what extent, the levels of HP cross-link changes in diaphragm muscle in the mdx mouse.…”

Therapeutic Effect of Extracorporeal Shock Wave Therapy According to Treatment Session on Gastrocnemius Muscle Spasticity in Children With Spastic Cerebral Palsy: A Pilot Study

“…Compared to a normal muscle cell, a spastic muscle cell has a shorter resting sarcomere and a higher elastic modulus, implying dramatic remodeling of intra- and extra-cellular structural components such as titin and collagen [ 23 ]. Collagen plays an important physiological role in the development of muscle stiffness [ 24 ]. Inactivity in children with spastic CP can increase non-reducible collagen content in the spastic muscle, leading to muscle weakness, disuse muscle atrophy, and muscle shortening [ 5 ].…”

Comparison of Treatment Effects Between Children With Spastic Cerebral Palsy Under and Over Five Years After Botulinum Toxin Type A Injection

“…In comparison with a normal muscle cell, a spastic muscle cell has a short resting sarcomere and an increased elastic modulus, implying dramatic remodeling of intra- and extra-cellular structural components, such as titin and collagen [20]. Collagen has an important physiological role in the development of muscle stiffness [21]. In children with spastic CP, non-reducible collagen content in the spastic muscle increases with age, because inactivity due to muscle spasticity leads to muscle weakness, disused muscle atrophy and muscle shortening [13].…”