Figure 6

Effect of apigenin on cyclooxygenase 2 (COX-2) expression and apoptosis. Intracellular COX-2 expression followed treatment with apigenin or vehicle for 3 months. (a) COX-2 expression in representative histograms of spleen cell subsets. (b) Representative dot plot of gated CD4 T cells (percentage shown in right upper quadrant). (c) Compiled results from three experiments. Treatment with apigenin markedly suppressed COX-2 expression in gated CD4⁺ T cells, B cells, dendritic cells (DCs), and macrophages, but there was no difference in total CD11b⁺ cells or CD8⁺ T cells. (d) In vitro treatment with apigenin induced apoptosis of lupus T cells, B cells, DCs, and macrophages from SNF1 mice after 24-hour incubation. Culture with 30 μM apigenin resulted in a twofold increase in percentage of specific apoptosis in DCs and macrophages than in T and B cells. Apoptotic cells were analyzed in gated cell subsets to calculate percentage of specific apoptosis, as described in Materials and methods (n = 5 per stain). *P < 0.001, **P < 0.01, ^xP < 0.02, and ⁺P < 0.05 for (c) and (d). SNF1, (SWR × NZB)F1.