This study assessed the protective effect of melatonin against muscle atrophy provoked by chronic immobi
ization stress (CIS). CIS was induced in rats by limiting their trunk movement for 90min daily for 6 weeks.
Rats subjected to the CIS procedure demonstrated a substantial decrease in body weight, an increase in serum
corticosterone, muscle atrophy, and an increase in atrogin-1 mRNA levels. An increase in the serum lac
ate-to-pyruvate ratio and the oxidative stress accompanied by a reduction of Na+/K+ ATPase activity could
be responsible for these changes. Melatonin efficiently attenuated CIS-induced deleterious effects on the mus
cle by reducing corticosterone levels, the lactate-to-pyruvate ratio, and oxidative stress, thereby improving
Na+/K+ ATPase activity and muscle condition. We conclude that melatonin can contribute to the prevention
of CIS-induced muscle atrophy via its anti-stress, anti-oxidant properties and its effect on Na+/K+ ATPase ac
ivity.