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


CONCLUSIONS
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.
Lee
Sung Won
SW
Dong-A University, Seo-Gu, Busan, South Korea.
Song
Yeon Suk
YS
Shin
Sang Hwa
SH
Kim
Kyung Taek
KT
Park
Young Chul
YC
Park
Bong Soo
BS
Yun
Il
I
Kim
Kunhong
K
Lee
Sang Yeob
SY
Chung
Won Tae
WT
Lee
Hye Jeong
HJ
Yoo
Young Hyun
YH
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D002358:Cartilage, Articular / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D047390:Casein Kinase II / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D000077407:Cilostazol; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D009569:Nitric Oxide / Q000009:adverse effects / Q000494:pharmacology*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D020370:Osteoarthritis, Knee / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D013777:Tetrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D051023:BH3 Interacting Domain Death Agonist Protein; C494816:Bid protein, rat; D010726:Phosphodiesterase Inhibitors; D013777:Tetrazoles; D016159:Tumor Suppressor Protein p53; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D047390:Casein Kinase II; D048051:p38 Mitogen-Activated Protein Kinases; D020169:Caspases; D000077407:Cilostazol