Novel Biphasic Role of Resolvin D1 on Expression of Cyclooxygenase-2 in Lipopolysaccharide-Stimulated Lung Fibroblasts Is Partly through PI3K/AKT and ERK2 Pathways

Figure 3

The Effect of resolvin D1 on expression of COXs (COX-1 and COX-2) and PGE₂ and PGD₂ production at 48 hours in lung fibroblasts stimulated with LPS. ((a1), (a2), (c1), (c2)) HFL-1 cells were incubated with LPS after 48 hours in the presence or absence of 10, 50, or 100 nM of resolvin D1. COX-2 protein was detected by western blot (^∗𝑃<0.05 versus control, ^#𝑃<0.05 versus LPS, LPS + resolvin D1 (10 nM) groups). No significant change in the protein expression of COX-1 was observed after treatment with LPS in HFL-1 cells. ((e1), (e2)) Supernatants from HFL-1 cells treated with resolvin D1 at 0, 10, 50, or 100 nM in the presence of LPS (1 μg/mL) for 48 hours were collected and PGE₂ protein was measured by ELISA. Data are expressed as mean ± SE for each group (e1) (^∗𝑃<0.05 versus control). PGD₂ protein was measured by ELISA. Data are expressed as mean ± SE for each group (e2) (^∗𝑃<0.05 versus control, ^#𝑃<0.05 versus LPS group). ((b1), (b2), (d1), (d2), (f1), (f2)) We also dulicated our test in primary rat lung fibroblasts. (d1) (^∗𝑃<0.05 versus control, ^#𝑃<0.05 versus LPS group). (d2) There was no significant change in COX-1 expression after LPS treatment in primary rat lung fibroblasts. (^∗𝑃<0.05 versus control, (f1)). (^∗𝑃<0.05 versus control, ^#𝑃<0.05 versus LPS group, (f2)). All experiments were repeated in triplicate.