Kobe Journal of Medical Sciences, 2000


Takafumi ONGA***, Ryuichi SAURA*, Kosaku MIZUNO*, Hiroshi ITOH**

*Department of Orthopaedic Surgery, Kobe University School of Medicine 
**First Division, Department of Pathology, Kobe University School of Medicine 

Kobe J. Med. Sci. 46, 155-169, August 2000

AB: Both nitric oxide (NO) and prostaglandin E2 (PGE2) are known to play an important role in cartilage metabolism. The present study investigated the novel intercellular mechanism of inducible NO synthase (iNOS) induction mediated by PGE2 in articular 
chondrocytes. Bovine articular chondrocytes were stimulated by cyclic adenosine monophosphate (cAMP) elevating agents like PGE2 in the presence of interleukin- Ib (IL-Ib). NO generation was measured by using the Griess reaction. Inducible NOSmRNA was semi-quantitated by reverse transcription-polymerase chain reaction (RT PCR). While little NO was released from articular chondrocytes in the presence of PGE2 or direct adenylate cyclase activator such as forskolin, synergistic augmentation of NO generation was observed when chondrocytes were stimulated by PGE2 or forskolin in combination with IL-I?. Further expression of iNOS mRNA by stimulation of PGE2 in the presence of IL-Ib simultaneously was also detected by RT-PCR in comparison with the mRNA induction by IL-Ib stimulation alone. These results indicated that PGE2 might modulate the articular cartilage metabolism by augmentation of chondrocyte NO synthesis in inflammatory process through cAMP-protein kinase A system.

Published Bimonthly by Kobe University School of Medicine, Kobe, Japan