22) Osteoarthritis and Cartilage 15: December 2007
THE EFFECT OF DISTILLED METHYLSULFONYLMETHANE (MSM) ON HUMAN CHONDROCYTES IN VITRO
Purpose:Osteoarthritis (OA) is a joint disease characterized bya degenerative change of articular cartilage and underlying sub-chondral bone and often accompanied by inflammation. MSM,a dietary supplement composed of about 34% sulfur and self-affirmed as GRAS (generally recognized as safe) in the U.S.,is most utilized for treating osteoarthritis. A recent study by Kimet. al., OA & Cart, 2006, showed clinical effectiveness of MSMsupplementation at 3 gm BID x 12 weeks compared to placebo.The objective of our study was to examine the effect of MSMat varying concentrations on cultured human healthy and os-teoarthritic chondrocytes in vitro with a focus on catabolic andanabolic markers.Methods:Human cartilage tissues were obtained from 22 knees,72 hrs postmortem from donors with different grades of OA. Weused the Outerbridge classification (Grades I – IV), Grade I forintact surface; Grade II for minimal fibrillation; Grade III for overtfibrillation; and Grade IV for erosion of the articular cartilagesurface. Following gross assessment of the donor knees, thefollowing knees were studied for Grade I (n=6) (aged 23-38);Grade II (n=9) (aged 50-77); for Grade III (n=5) (aged 32-70);and Grade IV (n=2) (aged 70-93). Cartilage tissues were har-vested from femoral condyles and tibial plateaus, the matrix wasdissolved with collagenase; the chondrocytes were then culturedfor 2 weeks in culture media without MSM. After reaching con-fluence, the chondrocytes were harvested and 2 x 105cells in10 ml culture medium with varying concentrations of MSM (0, 1,3, 6, 12, and 60μg/ml) were cultured in 100 mm (in-diameter)plates at 37°C in 5% CO2for 3 days. The concentrations wereestimated to correspond to human, oral dosing at between 0and 30 grams of MSM per day. mRNA expression of variousmarkers by RT-PCR including: TNF-alpha, IL-1, MMP-1, MMP-3,and MMP-13 was also determined for each OA grade and eachconcentration of MSM or control. Anabolic pathways examinedincluded proteoglycan synthesis (by a pulse chase analysis of35SO4 incorporation) and chondrocyte mRNA expressions ofType-II collagen and aggrecan. A one-way ANOVA was per-formed to establish the level of statistical significance.Results:In Grade II OA chondrocytes treated with MSM at theconcentration of 12μg/ml, there was a strong trend for MSMto reduce the mRNA expression of inflammatory markers: TNF-alpha (-33%, p=0.08) and IL-1 (-29%, p=0.08) when compared tolower concentrations of MSM and control. These results did notapply for OA chondrocytes of Grade III or IV. MSM did not showan increase in proteoglycan synthesis in cultured chondrocytesor an increase of cartilage matrix production in normal andosteoarthritic chondrocytes at the mRNA level.Conclusions:MSM might have an ability to protect articularcartilage in early OA by reducing expression of inflammatory cy-tokines, i.e. TNF-alpha & IL-1. The effective concentration of 12μg/ml MSM correlates with the dosage used in a recent clinicaltrial.