Fig. 2: opa1 RNAi impairs planarian regeneration and induces alterations in mitochondrial dynamics.

A Representative images show regeneration outcomes in live animals of egfp RNAi, opa1 RNAi, and drp1 RNAi animals at 7 dpa. Dpa, days post-amputation. n = 10 for each RNAi treatment. Scale bar, 500 μm. B In situ probes for chat and gata4/5/6 were used to show regeneration defects of the central nervous system and intestine in opa1 RNAi animals compared with egfp RNAi and drp1 RNAi animals at 7 dpa. n = 4 for each condition. Scale bar, 500 μm. C TEM images of planarian neoblasts (upper row) display the morphology of mitochondria in egfp RNAi, opa1 RNAi, and drp1 RNAi animals. Cells with neoblast characteristics were selected for observation. The experiment was repeated three times. The lower-row images correspond to the boxed areas in the upper-row images. Scale bars, 1 μm. D Representative Hessian-SIM images of mitochondria in Mito^low cells from egfp RNAi, opa1 RNAi, and drp1 RNAi planarians. Scale bar, 1 μm. E–H Dot plots of mitochondrial size (E), total length (F), branch length (G), and length/branch ratio (H) of Mito^low cells from egfp RNAi (n = 24), opa1 RNAi (n = 38), and drp1 RNAi (n = 35) planarians. The quantification is shown as mean ± SEM. Unpaired two-tailed Student’s t test was used to determine the significance of differences between two conditions. I Pseudocolor dot plots show Mito^low and Mito^high cells with their percentages from egfp RNAi and opa1 RNAi animals. Mito^low: p-value = 2.56 × 10^-5 (72.9 ± 1.13% vs. 88.8 ± 0.80%); Mito^high: p-value = 7.78 × 10^-5 (20.6 ± 0.67% vs. 6.4 ± 0.74%) as opa1 RNAi versus egfp RNAi controls. The quantification is shown as mean ± SEM. Unpaired two-tailed Student’s t test was used to determine the significance of differences between two conditions.