Figure 5From: Octacalcium phosphate crystals directly stimulate expression of inducible nitric oxide synthase through p38 and JNK mitogen-activated protein kinases in articular chondrocytesp38 and JNK MAPK pathways regulate OCP crystal induced NO production and iNOS mRNA expression. Nonadherent bovine articular chondrocytes were stimulated with OCP crystals or IL-1β for 24 hours with or without pretreatment (1 hour) with (a,c) SB 203580 (a p38 MAPK inhibitor), (b,c) JNK II inhibitor or (d) PD 58059 (an Erk1/2 MAPK inhibitor). iNOS transcripts (panel d) were assessed 8 hours after stimulation by OCP crystals or IL-1β by RT-PCR. The RT-PCR was representative of three experiments. GAPDH, glyceraldehyde-3-phosphate dehydrogenase; iNOS, inducible nitric oxide synthase; JNK, c-Jun amino-terminal kinase; NO, nitric oxide; OCP, octacalcium phosphate.Back to article page