Relationship between extracellular matrix, contractile apparatus, muscle mass and strength in case of glucocorticoid myopathy

Degradation of myofibrillar proteins increased from 2.62 ± 0.28 to 5.58 ± 0.49% per day during glucocorticoids excess. Both fibril- and network-forming collagen-specific mRNA levels decreased at the same time in both types of skeletal muscle. Specific mRNA level for MMP-2 did not change significantly during dexamethasone administration. Hindlimb grip strength simultaneously decreased. The effect of excessive glucocorticoids on the extracellular compartment did not differ significantly in skeletal muscles with different twitch characteristics.