(A-G) At the L4 larval stages, WT and pmp-4(ok396) nematodes were treated with CoQ (1 mg/ml) or MitoQ (5 μg/ml) for 7 days. (A) The thrashing behaviour was carried out in WT and pmp-4(ok396) nematodes upon CoQ or MitoQ at L4+7 days (n=15 to 27 animals by condition). Representative fluorescence images showing axonal abnormalities and quantitative analysis at the indicated genotypes upon CoQ or MitoQ at L4+7 days in (B) juIs76 [Punc-25::gfp] (n=20), (C) pmp-4(ok396); juIs76 [Punc-25::gfp] (n=20), (D) juIs76 [Punc-25::gfp] + CoQ (n=18), (E)pmp-4(ok396); juIs76 [Punc-25::gfp] + CoQ (n=15), (F) juIs76 [Punc-25::gfp] + MitoQ (n=26) and (G) pmp-4(ok396; juIs76 [Punc-25::gfp]) + MitoQ (n=27). White asterisks indicate axonal abnormalities. All worms are oriented with the anterior end left and ventral side down. Scale = 25 μm. (H-N) At the L4 larval stage, juIs76 [Punc-25::gfp]and pmp-4(ok396); juIs76 [Punc-25::gfp] nematodes were treated with paraquat (PQT) (0.2 mM) and/or MitoQ (5 μg/ml) for 7 days. (H) The thrashing behaviour was analysed at stage L4+7 days in WT and pmp-4(ok396) nematodes upon PQT and/or MitoQ (n=20 to 31 animals by condition). Representative fluorescence images showing axonal abnormalities and quantitative analysis at stage L4+7 days in (I) juIs76 [Punc-25::gfp]) (n=29), (J) pmp-4(ok396); juIs76 [Punc-25::gfp] (n=31), (K) juIs76 [Punc-25::gfp] + PQT(n=25), (L) pmp-4(ok396); juIs76 [Punc-25::gfp] + PQT (n=20), (M) juIs76 [Punc-25::gfp] + PQT + MitoQ (n=21), (N) pmp-4(ok396; juIs76 [Punc-25::gfp] + PQT + MitoQ (n=28). Scale = 25μm. All worms are oriented with the anterior end left and ventral side down. Data represent the mean ± standard deviation (SD). Statistical analysis was carried out with two-way ANOVA, followed by Tukey’s post hoc test (*P<0.05; **P<0.01; ***P<0.001) for A-N.