Effect of insulin on dexamethasone-induced ultrastructural changes in skeletal and cardiac muscle

Abstract

Glucocorticoids help animals respond to stressors but excessive glucocorticoids cause muscle atrophy, while insulin can promote anabolism and growth. In order to compare the glucocorticoids-induced ultrastructural changes between skeletal muscle and cardiac muscle, and investigate the preventive effects of insulin on the changes, eighteen male chicks with similar initial weight were randomly divided into three groups. The two test groups were respectively treated with high-dose dexamethasone alone or together with low-dose insulin by intraperitoneal injection, and the control group was treated with an equal volume of saline solution. The experiment lasted for ten days, and then the body weight, muscle size and ultrastructure in skeletal and cardiac muscles of twelve chicks were qualitatively or quantitatively analyzed. The results showed that high-dose dexamethasone induced obvious skeletal and cardiac muscle atrophy. The differences of ultrastructural changes between skeletal muscle and cardiac muscle (such as for the former or the latter, the intermyofibrillar-and-interfilamentary spaces reducing or enlarging, the mitochondria swelling seriously or enlarging lightly, the myofibril filaments compacting or loosing) suggested that dexamethasone induced skeletal and cardiac muscle atrophy by different mechanisms. Low-dose insulin did not affect the dexamethasone-induced decreases of body weight and skeletal muscle size, but alleviated lightly the dexamethasone-induced ultrastructural changes in skeletal muscle. Different from skeletal muscle, low-dose insulin almost resisted the dexamethasone-induced ultrastructural changes in cardiac muscle.

Omega-3 fatty acids reduce the negative effects of dexamethasone-induced physiological stress in laying hens by acting through the nutrient digestibility and gut morphometry

“…In this study, the increased liver weight and decreased BW in stressed birds were in accordance with the previous ones ( Shini et al., 2009 ; Wang et al., 2013 ). Similar to the results of this experiment, an elevated relative weight of the heart after DEX treatment has been reported ( Qin et al., 2012 ). The decrease of BW after DEX administration indicates the enhanced protein catabolism in stressed laying hens.…”

Effects of intermittent pressure imitating rolling manipulation on calcium ion homeostasis in human skeletal muscle cells

“…The human skeletal muscle injury modeling cells were induced by dexamethasone according to the reference literature [ 26 ]. Some researches conformed that excessive dosage of dexamethasone could produce injury to muscle cells by suppressing cells proliferation, reducing SOD level, increasing MDA, and causing intracellular Ca 2+ overloading [ 27 , 28 ].…”