Effects of L-Carnitine on Disuse Muscle Atrophy

Abstract

Immobilization stress induces the formation of reactive oxygen species and leads to oxidative injury in various tissues. Lipid peroxidation is the most important mechanism in muscle atrophy. L-carnitine may prevent lipid peroxidation and may thus protect against muscle atrophy. PURPOSE: The aim of this study is to determine the effect of l-carnitine supplementation on disuse muscle atrophy. METHODS: Twenty-seven male Sprague Dawley rats were divided into 4 groups: control 21 (CONT), days of hindlimb unloading (HU), 21 days of hindlimb unloading + L-carnitine (HU + LC), and control L-carnitine (LC-CONT). The rats from the HU and HU + LC groups were suspended for 21 days according to the tail suspension model described by Morey-Holton and Globus. The soleus and extensor digitorum longus muscles from both hindlimbs were dissected, and the wet tissue weights were measured. The level of MDA, which is a marker for lipid peroxidation, was determined in the homogenates according to the thiobarbituric acid reaction described by Buege and Aust. The GSH levels were assayed in tissue homogenates according to the method of Ellman. All experimental procedures involving animals were approved by the ethical committee for animal research of the Baskent University Faculty of Medicine in Ankara, Turkey. RESULTS: Muscle unweighting caused a 33% decrease in the soleus muscle and a 20% decrease in the EDL mass. The GSH level was statistically significantly higher in the LC-CONT group than in the CONT, HU + LC, and HU groups. The GSH level in the HU group was statistically significantly lower than that in the HU + LC group. The GSH content was not found to be statistically significantly different in the HU group and the HU + LC group from that in the CONT group. MDA levels were statistically significantly lower in the HU + LC and LC-CONT groups than those in the CONT group and statistically significantly lower in the HU + LC group than those in the HU group (P < .0125). CONCLUSION: We concluded that L-carnitine reduced the degree of muscle atrophy and oxidative stress caused by 21 days of immobilization.