Figure 5

(A) Confocal Z-plane projections showing mCerulean-labeled mitochondria in the lateral line nerves of live NeuMitoFAP zebrafish in the absence (upper images) or presence (lower images) of MG2I, before (upper image of each pair) or after (lower image of each pair) exposure to 60 J/cm2 light at λpeak=661 nm. (B - D) The (B) number of mitochondria per field, (C) mitochondrial length, and (D) mitochondrial circularity were quantified in z-plane projections of the entire medio-lateral extent of the lateral line nerve in 6 zebrafish per group. Bars show mean ± 95% CI for NeuMitoFAP zebrafish in the absence (blue) or presence (red) of MG2I, before or after exposure to far-red light. Data points show individual zebrafish (panel B) or individual mitochondria (panels C, D). ***p<0.001, ****p<0.0001, NeuMitoFAP-MG2I post-light versus each other group individually, 1-way ANOVA with Tukey multiple comparisons test. (E, F) Transmission electron micrographs of sections from the telencephalon of NeuMitoFAP zebrafish immediately after exposure to far-red light in the (F) presence or (E) absence of MG2I. The left image of each pair shows a low-magnification view, and the right image shows a high-magnification view illustrating the ultrastructure of individual neuronal mitochondria. Arrows in panel F show swollen, damaged mitochondria. (G) The proportion of abnormal mitochondria was quantified by a blinded observer in 12 electron micrographs each from 6 experimental groups (NeuMitoFAP with or without MG2I, before, 0 or 24 hr after 60 J/cm2 far-red light exposure). Bars show mean ± SE% abnormal mitochondria per section in each group. Numbers of total and abnormal mitochondria in each group are shown. ***p<0.001, compared individually with each control (pre-light and no chemical) group, 1-way ANOVA with Tukey multiple comparisons test.