Figure 6
Effect of prostaglandin E (EP) receptor ligands on proliferation of cultured chondrocytes. (a) Unselective and selective EP receptor agonists were administered to cultured chondrocytes. Subconfluent chondrocytes were synchronized in serum-free medium for 24 hours and EP receptor agonists were added for 24 hours. Proliferation was assessed by [3H]thymidine incorporation. C, control; Sul, 1 μM sulprostone; Miso, 1 μM misoprostole; But, 1 μM butaprost; EP1A, 4 μM ONO-D1-004; EP2A, 0.1 μM ONO-AE1-259-01; EP3A, 0.1 μM ONO-AE-248; EP4A, 0.1 μM ONO-AE1-329. Data are given as mean ± standard error of the mean, n = 5. *P value < 0.05. (b) To study EP1 function for cell growth, a EP1 receptor selective agonist and antagonist were added to cultured chondrocytes. Subconfluent chondrocytes were synchronized in serum-free medium for 24 hours and EP1 receptor agonist (EP1A) or antagonist (EP1AN) combined with 10 nM prostaglandin E2 were added for 24 hours in the presence of [3H]-thymidine. EP1A, 4 μM ONO-D1-004; EP1AN, 1 μM ONO-8711. Data are given as mean ± standard error of the mean, n = 5. *P value < 0.05.