Fig. 6

Injection of the chemokines CXCL8 and CCL2 rescued the impaired regeneration caused by GM6001. (A) The heart of Tg (coro1a:EGFP; lyz:dsRed) fish were cryoinjured and injected with (Aa) DMSO alone (control); (Ab) GM6001 and PBS; or (Ac) GM6001 and chemokines, after which the numbers of neutrophils (labeled in yellow) and macrophages (labeled in green) were quantified. Scale bar: 200 µm. (Ad) Bar graph to show the numbers (mean ± standard deviation) of neutrophils and macrophages per mm³ in the IA of fish at 1 dpc following the treatment regimens conducted in (Aa–Ac). Statistical analysis was carried out by One-way ANOVA with LSD Post-hoc test and significant differences (at p < 0.05) are shown by the different symbols (α, β, αβ and §, #) above the bars for the neutrophils and macrophages. (B) Wild type fish hearts were cryoinjured and then either (Bb) PBS or (Bc) chemokines were injected into the injured area following daily treatment with GM6001 during the first week after injury. (Ba) Some fish were injected with DMSO as a blank control. Serial paraffin heart sections were prepared and stained with picrosirius red. ‘V’ and ‘S’ are the ventricle and scar of the IA, respectively. Scale bar: 200 µm. (Bd) Bar graph to show the percentage of scar volume in the ventricle following the different treatments. The data are expressed as mean ± standard deviation of n = 5 to 6 hearts. The asterisks indicate significantly different data at p < 0.01, and ‘n.s.’ indicates results where no statistically significant differences were found, one-way ANOVA with LSD Post-hoc test.