Fig. 4

Fig. 4

a–e Single-plane confocal images of control (a), methotrexate-treated (b), Tg(actb2:folr1) (c) and Tg(actb2:folr1) cotreated with methotrexate (d) islets following 2 days of β-cell regeneration. Quantification showed that the number of regenerating β-cells upon Tg(actb2:folr1) overexpression was reduced to the baseline level after treatment with methotrexate (e). Scale bar, 10 μm. n = 14 control, n = 16 methotrexate-treated, n = 16 Tg(actb2:folr1), and n = 16 Tg(actb2:folr1) cotreated with methotrexate biologically independent zebrafish larvae were used for the quantification of β-cells. Data are presented as mean values ± SEM. One-way ANOVA was used to assess significance followed by Holm–Sidak’s multiple comparison test. *P = 0.0120. f–i Folinic acid treatment for two days following β-cell ablation increased β-cell regeneration from ductal cells by 6 dpf in zebrafish larvae. Single-plane confocal images of Tg(ins:H2BGFP);Tg(ins:flag-NTR);Tg(tp1:H2BmCherry) control (f) and folinic acid-treated (g) larvae, along with the quantification of the β-cells (h) and the β-cells co-labeled with the ductal cell tracer tp1:H2BmCherry (i). Scale bar, 10 μm. n = 17 (control) and n = 15 (folinic acid) biologically independent zebrafish larvae were used for the quantification of this experiment. Data are presented as mean values ± SEM. Unpaired two-tailed Student’s t test was used for (h) **P = 0.0064. Unpaired two-tailed Student’s t-test was used to assess significance for (i) **P = 0.0094.