TRAIL induces apoptosis of chondrocytes and influences the pathogenesis of experimentally induced rat osteoarthritis

Self Cite

Objective. To examine whether cilostazol, a selective phosphodiesterase type III inhibitor, protects rat articular chondrocytes against nitric oxide (NO)-induced apoptosis and prevents cartilage destruction in mono-iodoacetate-induced osteoarthritis (OA) in a rat model in which inducible nitric oxide synthase (iNOS) is expressed.Methods. The NO donor sodium nitroprusside was administered to rat articular chondrocytes that had been pretreated with cilostazol. Induction of apoptosis was evaluated by DNA electrophoresis and pulsed-field gel electrophoresis. The expression level and the subcellular location of apoptosis-associated factors were examined by Western blot analysis and confocal microscopy, respectively. Protein kinase CK2 (PKCK2) activity was also assayed. To examine whether orally administered cilostazol prevents cartilage destruction in vivo, cartilage samples obtained from rats with experimentally induced OA were subjected to hematoxylin and eosin, Safranin O, and TUNEL staining and immunohistochemical analysis of iNOS expression.Results. Cilostazol prevented NO-induced reduction in viability, in a dose-dependent manner. It also prevented the up-regulation of phosphorylated p53 and p38, the down-regulation of heme oxygenase 1, the subcellular translocation of apoptosis-inducing factor and cytochrome c, and the activation of caspases 3, 7, and 8 induced by NO treatment, indicating that cilostazol prevented NO-induced cell death by blocking apoptosis. In addition, cilostazol prevented NO-induced translocation of cleaved Bid onto mitochondria, and caused phosphorylated Bid to accumulate in the nucleus and cytosol. Cilostazol prevented the down-regulation of PKCK2 and the reduction in PKCK2 activity induced by NO, indicating that its apoptosis-preventing activity was mediated via PKCK2. It also prevented chondrocyte apoptosis and cartilage destruction in a rat model of experimentally induced OA. Conclusion. Our findings indicate that cilostazol prevents NO-induced apoptosis of chondrocytes via PKCK2 in vitro and prevents cartilage destruction in a rat model of OA.

Section: Conclusion Our Findings Indicate That Cilostazol Prevents Nmentioning

confidence: 99%

Section: Conclusion Our Findings Indicate That Cilostazol Prevents Nmentioning

confidence: 99%

Section: Conclusion Our Findings Indicate That Cilostazol Prevents Nmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Cilostazol protects rat chondrocytes against nitric oxide–induced apoptosis in vitro and prevents cartilage destruction in a rat model of osteoarthritis

Lee

Song

Shin

et al. 2008

Self Cite

“…Decreased chondrocyte density and cell death are considered features of OA cartilage (8). Several potential mechanisms of chondrocyte death have been proposed, including production of oxygen and nitrogen radicals, death receptor activation, and mechanical stress (9)(10)(11). GAG loss is known to occur in response to mechanical injury and is linked with chondrocyte death (12,13).…”

mentioning

confidence: 99%

The effect of glycosaminoglycan loss on chondrocyte viability: A study on porcine cartilage explants

Otsuki¹,

Brinson²,

Creighton³

et al. 2008

Objective. Loss of glycosaminoglycan (GAG) is an early event in osteoarthritis. Recent findings showed increased cell death in arthritic cartilage and linkage with extracellular matrix degradation. The aim of this study was to analyze the direct effect of GAG loss on chondrocyte survival and cell death following mechanical injury.Methods. In full-thickness cartilage explants from porcine knee joints, GAG was depleted by digestion with chondroitinase ABC. Explants were subjected to single-impact mechanical injury. Cell viability and the types of cell death were analyzed by Live/Dead cell assay, staining for active caspase 3, and sensitivity to caspase inhibitor.Results. GAG depletion did not directly lead to increased cell death. In chondroitinase ABC-treated explants, but not in control explants, mechanical injury caused an immediate reduction in cell viability (from 84.6% to 71.0%); the reduction was prominent in the superficial zone. This immediate cell death was not inhibited by the pancaspase inhibitor Z-VAD-FMK, suggesting cell necrosis. During subsequent culture, viability in these explants decreased further, to 50.5% on day 3. The second wave of cell death was reduced by the addition of Z-VAD-FMK in chondroitinase ABC-treated explants and was also associated with activation of caspase 3, suggesting apoptotic mechanisms of cell death.Conclusion. These results indicate that GAG loss alone does not directly lead to chondrocyte death. In response to mechanical injury, there is an immediate induction of necrotic cell death that is seen only in GAG-depleted explants and primarily in the superficial zone. During subsequent culture, cell death spreads via apoptotic mechanisms.

Caspase inhibitors reduce severity of cartilage lesions in experimental osteoarthritis

D’Lima

Hermida

Hashimoto

et al. 2006

155

117

Objective. To examine the therapeutic efficacy of caspase inhibitors in experimental osteoarthritis (OA).Methods. Experimental OA was induced in rabbits by anterior cruciate ligament transection (ACLT). Rabbits were treated with intraarticular (IA) injections of caspase inhibitors 3 times per week starting 1 week postoperatively. Animals were killed 9 weeks after ACLT, for macroscopic, histologic, and immunohistochemical assessment of the knee joints.Results. IA administration of the pan-caspase inhibitor Z-VAD-FMK significantly reduced cartilage degradation, as assessed by macroscopic and microscopic criteria. Untreated knees showed large numbers of chondrocytes with active caspase 3 and the p85 fragment of poly(ADP-ribose) polymerase (PARP p85) that is generated during apoptosis. The frequency of cells positive for PARP p85 and active caspase 3 was reduced in Z-VAD-FMK-treated knees. Inhibitors specific for caspase 3 or caspase 8 showed no significant efficacy. Caspase 1 inhibitor and the combination of caspase 3 and caspase 8 inhibitors reduced OA pathology.Conclusion. These results provide direct support for a role of cell death in OA pathogenesis. Caspase inhibitors reduced the severity of cartilage lesions in experimental OA, suggesting that they may have disease-modifying activity in human OA.