Aru Maire, Alev Karin, Pehme Ando, Purge Priit, Õnnik Lauri, Ellam Anu, Kaasik Priit, Seene Teet
Institute of Sport Sciences and Physiotherapy, University of Tartu, Ravila 14a, 50411 Tartu, Tartu, Estonia.
Curr Aging Sci. 2019;11(4):255-260. doi: 10.2174/1874609812666190114144238.
Aging leads to changes in skeletal muscle quantity and quality and is accompanied with increase in body mass and fat mass, whereas fat-free mass either decreases or remains unchanged. The body composition of rodents has been an important factor for clinical trials in the laboratory. Glucocorticoids such as dexamethasone are widely used in clinical medicine, but may induce myopathy, characterized by muscle weakness, atrophy, and fatigue. In animals treated with glucocorticoids, a dose-dependent reduction of body weight has been observed. This weight loss is usually followed by muscle atrophy and a reduction of several muscle proteins, contributing to impaired muscle function. This study was designed to describe changes in body composition and BMC of 22-month-old rats during 10- and 20-day recovery period after 10-day dexamethasone administration.
Data on body mass, lean body mass, fat mass and bone mineral content of the rats were obtained with dual energy X-ray absorptiometry scan.
Significant reduction in body mass, lean body mass, fat mass and fast-twitch muscle mass was observed after dexamethasone treatment. Body mass, fat mass and fast-twitch muscle mass stayed decreased during 20 days after terminating the hormone administration; lean body mass reached the preadministration level after 20-day recovery period. There were no significant changes in bone mineral density during the recovery period. Dexamethasone treatment gradually reduced hindlimb grip strength that also stayed decreased during the 20-day recovery period.
This study demonstrated that a 10-day period of overexprosure to glycocorticoids induced longlasting changes in old rats' body composition and these values did not attain the baseline level even after 20-day recovery period.
衰老会导致骨骼肌数量和质量发生变化，并伴随着体重和脂肪量增加，而去脂体重则会减少或保持不变。啮齿动物的身体组成一直是实验室临床试验的一个重要因素。地塞米松等糖皮质激素在临床医学中广泛使用，但可能会诱发肌病，其特征为肌肉无力、萎缩和疲劳。在用糖皮质激素治疗的动物中，已观察到体重呈剂量依赖性下降。这种体重减轻通常随后会出现肌肉萎缩和几种肌肉蛋白减少，从而导致肌肉功能受损。本研究旨在描述22月龄大鼠在给予地塞米松10天后10天和20天恢复期内身体组成和骨矿物质含量的变化。
通过双能X线吸收法扫描获得大鼠的体重、瘦体重、脂肪量和骨矿物质含量数据。
地塞米松治疗后，体重、瘦体重、脂肪量和快肌质量显著降低。在停止激素给药后的20天内，体重、脂肪量和快肌质量持续下降；瘦体重在20天的恢复期后达到给药前水平。恢复期内骨矿物质密度无显著变化。地塞米松治疗逐渐降低后肢握力，在20天的恢复期内握力也持续下降。
本研究表明，10天的糖皮质激素过度暴露会导致老年大鼠身体组成发生长期变化，即使在20天的恢复期后，这些数值也未达到基线水平。
