Curcumin has been shown to exhibit anti-inflammatory, antimutagenic, and anticarcinogenic activities. However, the effect of curcumin on the maturation and immunostimulatory function of dendritic cells (DC) largely remains unknown. In this study, we examined whether curcumin can influence surface molecule expression, cytokine production, and their underlying signaling pathways in murine bone marrow-derived DC. DC were derived from murine bone marrow cells and used as immature or LPS-stimulated mature cells. The DC were tested for surface molecule expression, cytokine production, dextran uptake, the capacity to induce T cell differentiation, and their underlying signaling pathways. Curcumin significantly suppressed CD80, CD86, and MHC class II expression, but not MHC class I expression, in the DC. The DC also exhibited impaired IL-12 expression and proinflammatory cytokine production (IL-1β, IL-6, and TNF-α). The curcumin-treated DC were highly efficient at Ag capture, via mannose receptor-mediated endocytosis. Curcumin inhibited LPS-induced MAPK activation and the translocation of NF-κB p65. In addition, the curcumin-treated DC showed an impaired induction of Th1 responses and a normal cell-mediated immune response. These novel findings provide new insight into the immunopharmacological role of curcumin in impacting on the DC. These novel findings open perspectives for the understanding of the immunopharmacological role of curcumin and therapeutic adjuvants for DC-related acute and chronic diseases.
In the present study, we aimed to determine whether ethanol extracts of Fructus Schisandrae (FS), the dried fruit of Schizandra chinensis Baillon, mitigates the development of dexamethasone-induced muscle atrophy. Adult SPF/VAT outbred CrljOri:CD1 (ICR) mice were either treated with dexamethasone to induce muscle atrophy. Some mice were treated with various concentrations of FS or oxymetholone, a 17α-alkylated anabolic-androgenic steroid. Muscle thickness and weight, calf muscle strength, and serum creatine and creatine kinase (CK) levels were then measured. The administration of FS attenuated the decrease in calf thickness, gastrocnemius muscle thickness, muscle strength and weight, fiber diameter and serum lactate dehydrogenase levels in the gastrocnemius muscle bundles which was induced by dexamethasone in a dose-dependent manner. Treatment with FS also prevented the dexamethasone-induced increase in serum creatine and creatine kinase levels, histopathological muscle fiber microvacuolation and fibrosis, and the immunoreactivity of muscle fibers for nitrotyrosine, 4-hydroxynonenal, inducible nitric oxide synthase and myostatin. In addition, the destruction of the gastrocnemius antioxidant defense system was also inhibited by the administration of FS in a dose-dependent manner. FS downregulated the mRNA expression of atrogin-1 and muscle RING-finger protein-1 (involved in muscle protein degradation), myostatin (a potent negative regulator of muscle growth) and sirtuin 1 (a representative inhibitor of muscle regeneration), but upregulated the mRNA expression of phosphatidylinositol 3-kinase, Akt1, adenosine A1 receptor and transient receptor potential cation channel subfamily V member 4, involved in muscle growth and the activation of protein synthesis. The overall effects of treatment with 500 mg/kg FS were comparable to those observed following treatment with 50 mg/kg oxymetholone. The results from the present study support the hypothesis that FS has a favorable ameliorating effect on muscle atrophy induced by dexamethasone, by exerting anti-inflammatory and antioxidant effects on muscle fibers, which may be due to an increase in protein synthesis and a decrease in protein degradation.
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