title: The antioxidant resveratrol protects against chondrocyte apoptosis via effects on mitochondrial polarization and ATP production.
abstract: OBJECTIVE
  To determine the effects of the antioxidant resveratrol on the functions of human chondrocytes in osteoarthritis (OA).
  
  
  METHODS
  Chondrocytes and cartilage explants were isolated from OA patients undergoing knee replacement surgery. Effects of resveratrol in the presence or absence of interleukin-1beta (IL-1beta) stimulation were assessed by measurement of prostaglandin E(2) (PGE(2)) and leukotriene B(4) (LTB(4)) synthesis, cyclooxygenase (COX) activity, matrix metalloproteinase (MMP) expression, and proteoglycan production. To explore the mechanisms of action of resveratrol, its effects on mitochondrial function and apoptosis were examined by assessing mitochondrial membrane potential, ATP levels, cytochrome c release, and annexin V staining.
  
  
  RESULTS
  Resveratrol inhibited both spontaneous and IL-1beta-induced PGE(2) production by >20% (P < 0.05) and by 80% (P < 0.001), respectively; similarly, LTB(4) production was reduced by >50% (P < 0.05). The production of PGE(2) was inhibited via a 70-90% suppression of COX-2 expression and enzyme activity (P < 0.05). Resveratrol also promoted anabolic effects in OA explant cultures, by elevating proteoglycan synthesis and decreasing production of MMPs 1, 3, and 13. Pretreatment of OA chondrocytes with resveratrol blocked mitochondrial membrane depolarization, loss of mitochondrial biomass, and IL-1beta-induced ATP depletion. Similarly, IL-1beta-mediated induction of the apoptotic markers cytochrome c and annexin V was also inhibited by resveratrol. Exogenous addition of PGE(2) abolished the protective effects of resveratrol on mitochondrial membrane integrity, ATP levels, expression of apoptotic markers, and DNA fragmentation.
  
  
  CONCLUSIONS
  Resveratrol protects against IL-1beta-induced catabolic effects and prevents chondrocyte apoptosis via its inhibition of mitochondrial membrane depolarization and ATP depletion. These beneficial effects of resveratrol are due, in part, to its capacity to inhibit COX-2-derived PGE(2) synthesis. Resveratrol may therefore protect against oxidant injury and apoptosis, which are main features of progressive OA.
authors.affiliation: New York University Hospital for Joint Diseases, New York, New York 10003, USA.
authors.forename: Mandar
authors.initials: M
authors.lastname: Dave
authors.forename: Mukundan
authors.initials: M
authors.lastname: Attur
authors.forename: Glyn
authors.initials: G
authors.lastname: Palmer
authors.forename: Hayf E
authors.initials: HE
authors.lastname: Al-Mussawir
authors.forename: Lauren
authors.initials: L
authors.lastname: Kennish
authors.forename: Jyoti
authors.initials: J
authors.lastname: Patel
authors.forename: Steven B
authors.initials: SB
authors.lastname: Abramson