Mechanisms Underlying the Antifatigue Effects of the Mycelium Extract of <i>Cordyceps</i> (<i>Paecilomyces hepiali</i>, CBG-CS-2) in Mice in the Forced Swimming Test

Abstract

Cordyceps (CS) is used as an alternative medicine and functional food. We examined in vivo mechanisms underlying the antifatigue effects of the cultured mycelium extract of CS (CS extract) in forced swimming mice, a fatigue model that is induced by muscle exercise. Animals orally administered with CS extract significantly extended the loaded forced-swimming time, indicating its antifatigue effects. CS extract modulated the increased levels of blood IL-6 that was induced by forced swimming. CS extract protected the forced swimming-induced increase in NKp46 expression of splenic NK cells, suggesting regulation of fatigue-elicited hyper-reactivity by activated NK cells. By DNA microarray analysis of the quadriceps femoris muscle, it was uncovered that CS extract prevented the forced swimming-mediated upregulation of the expression of 5 genes associating with muscular inflammation ( Cc l6, Cc l8, and Wfdc 17) and muscle regeneration ( Sfrp 4 and Nfil 3), whereas it regulated the downregulation in the expression of Svs5 participating in actin binding. CS extract exhibits the antifatigue effects through preventing IL-6 accumulation in blood, regulating NK cell activation in the spleen, and alleviating altered expression of genes related to inflammation, regeneration, and actin binding in the local muscle. Thus, CS extract is an effective functional food for preventing fatigue.