Figure 4.

Effects of PLA₂ inhibitor and COX and LOX inhibitors on expression levels of Se-Duox. (a) Inhibitory effect of a PLA₂ inhibitor, dexamethasone (DEX), on Se-Duox expression in L5 larvae. For bacterial challenge, larvae were fed with E. coli (2 × 10⁴ cells/larva) treated artificial diet for 12 h. (b) Effects of DEX on ROS levels in gut lumen. To induce ROS, E. coli (2 × 10⁴ cells)-treated artificial diet was fed to larvae at 8 h post-injection of DEX. At 12 h after bacterial treatment, intestinal ROS levels were measured. (c) Influence of naproxene (‘Nap’, a COX inhibitor) and esculetin (‘Esc’, a LOX inhibitor) on expression of Se-Duox. (d) Effects of Nap and Esc on ROS levels in gut lumen. Each inhibitor was injected into larvae at a final concentration of 10 µg per larva. At 8 h post-injection of inhibitor, E. coli (2 × 10⁴ cells)-treated artificial diet were fed to larvae to induce Se-Duox expression and ROS. To rescue Se-Duox expression and ROS production, PGD₂ or PGE₂ was injected at 1 µg/larva. Each treatment was replicated three times. Each replication used 15 larvae. Different letters indicate significant differences among means at Type I error = 0.05 (LSD test).