Mesangial cell DNA synthesis induced by hydrogen peroxide, interleukin-6, and platelet-derived growth factor: effects of indomethacin and dazmegrel.

This study indirectly examined the role of prostanoids (PG) in mediating rat mesangial cell (MC) DNA synthesis induced by hydrogen peroxide (H2O2), interleukin 6 (IL-6), and platelet-derived growth factor (PDGF). MC were exposed to three daily pulses of 10(-6) mol/l H2O2 alone or in combination with IL-6 (5 ng/ml) or PDGF (10 ng/ml). In order to examine (indirectly) the role of PG in mediating changes in MC DNA synthesis, indomethacin (1.5 x 10(-5) mol/l) or the thromboxane A2 synthetase inhibitor Dazmegrel (10(-5) mol/l) was added to the medium and DNA synthesis assessed after 72 h using 3H-thymidine incorporation (3H-TdR). Stimulation of MC by H2O2 alone resulted in an increase in 3H-TdR of 34.7 +/- 5.5% (p < 0.01). H2O2 enhanced the mitogenic effects of IL-6 and PDGF, 3H-TdR increasing by 52 +/- 12.1% (p < 0.01) and 100 +/- 21% (p < 0.001), respectively. Indomethacin suppressed the DNA synthesis induced by H2O2 alone, 3H-TdR decreasing by 33 +/- 12% (p < 0.05). Indomethacin also reduced the mitogenic response to H2O2 plus IL-6 and H2O2 plus PDGF by 91 +/- 17 and 97 +/- 12%, respectively (p < 0.05). Dazmegrel reduced 3H-TdR when MC were exposed to H2O2 alone by 31.8 +/- 16% (p < 0.05) and when combined with IL-6 or PDGF by 80 +/- 26 and 120 +/- 13%, respectively (p < 0.05). These data suggest that the pathways through which H2O2-induced growth of MC is mediated appear, at least in part, to involve PG, particularly thromboxane A2.