mcu inactivation renders neuroprotection against MPTP. (A) Representative images of MPTP-untreated wt (a), pink1−/− (c), (pink1; mcu)−/− (e), mcu−/− (g) and MPTP-treated wt (b), pink1−/− (d), (pink1; mcu)−/− (f) and mcu−/− (h) 3 dpf larvae after WISH using TH-specific riboprobe. MPTP-treated wt (b) and pink1−/− (d) zebrafish larvae were most susceptible to MPTP toxicity while MPTP-untreated (pink1; mcu)−/− (e) and mcu−/− (g) were most resistant to MPTP toxicity. (B) Graphical representation of chromogenic WISH. There was a significant decrease (***P<0.001) in number of dopaminergic neurons in pink1−/− zebrafish treated with MPTP when compared to untreated pink1−/− zebrafish. MPTP-treated (pink1; mcu)−/− zebrafish showed a significant increase (***P<0.001) in number of dopaminergic neurons when compared to MPTP-treated pink1−/− zebrafish. Statistical analysis with one-way anova and post hoc analysis using Tukey's multiple comparison test of two different experiments with n=20. (C) Kaplan–Meier survival curves depicting survival rate for 5 days of wt, pink1−/−, mcu−/− and (pink1; mcu)−/− zebrafish treated with 25 µg ml-1 MPTP (n=100). Scale bars:100 µm.