Effect of SnPPIX, a HO-1 inhibitor, on fenofibrate-mediated protection of zebrafish neuromasts. (A) The neuromasts of zebrafish were (50 µM) for 1 h (GM, panels b and g), pre-treated with fenofibrate (10 µM) for 0.5 h and then co-treated with GM (500 µM) for 1 h (FF + GM, panels c and h), pre-treated with SnPPIX (10 µM) and fenofibrate (10 µM) for 0.5 h and then co-treated with GM (50 µM) for 1 h (SnPP + FF + GM, panels d and i), and fenofibrate alone (FF, panels e and j). One of the occipital neuromasts (OC1) is shown in panels a-e, and a posterior neuromast is (P1) shown in panels f-j. (B) Quantitative analysis of neuromast survival. Histogram represents the mean viability of neuromasts. Zebrafish were treated with medium alone (cont), GM (50 µM) for 1 h (OC and P1: 30.7±14.17, p≤ 0.001 and 24.2±9.29, p≤0.0002, respectively), pre-treated with fenofibrate (10 µM) for 0.5 h and then co-treated with GM (500 µM) for 1 h (OC and P1: 69.3±19.2, p≤0.003 and 72.5±17.86, p≤0.0006, respectively), pre-treated with SnPPIX (10 µM) and fenofibrate (10 µM) for 0.5 h and then co-treated with GM (50 µM) for 1 h (OC and P1: 38.6±10.00, p≤0.001 and 40.0±10.00, p≤0.002, respectively), and fenofibrate alone (FF). #p<0.005 by one-way ANOVA, compared to GM or SnPPIX + FF + GM. GM, gentamicin; FF, fenofibrate; SnPPIX, tin protoporphyrin IX; HO-1, heme oxygenase-1.