A biological extract of turmeric (Curcuma longa) modulates response of cartilage explants to lipopolysaccharide

Abstract

Background: Turmeric is commonly used as a dietary treatment for inflammation, but few studies have evaluated the direct effect of turmeric on cartilage. The purpose of this study was to characterize cartilage explants' inflammatory responses to lipopolysaccharide in the presence of a simulated biological extract of turmeric. Methods: Turmeric was incubated in simulated gastric and intestinal fluid, followed by inclusion of liver microsomes and NADPH. The resulting extract (TURsim) was used to condition cartilage explants in the presence or absence of lipopolysaccharide. Explants were cultured for 96 h (h); the first 24 h in basal tissue culture media and the remaining 72 h in basal tissue culture media containing TURsim (0, 3, 9 or 15 μg/mL). Lipopolysaccharide (0 or 5 μg/mL) was added for the final 48 H. media samples were collected immediately prior to lipopolysaccharide exposure (0 h) and then at 24 and 48 h after, and analyzed for prostaglandin E2 (PGE2), glycosaminoglycan (GAG), and nitric oxide (NO). Explants were stained with calcein-AM for an estimate of live cells. Data were analyzed using a 2-way repeated measures (GAG, PGE2, NO) or 1-way ANOVA without repeated measures (viability). Significance accepted at p < 0.05. Results: TURsim significantly reduced PGE2, NO and GAG, and calcein fluorescence was reduced. Conclusions: These data contribute to the growing body of evidence for the utility of turmeric as an intervention for cartilage inflammation.