Defective repair in cxcl12a (−/−) and cxcr4b (−/−) zebrafish embryos. a While control zebrafish embryos repair a lased-induced injury, more than 60% of cxcr4b-deficient zebrafish embryos (means ± SEM; ***p < 0.001; t-test) and b more than 40% of cxcl12a-deficient zebrafish embryos did not repair the wound, but instead revealed various abnormalities (means ± SEM; **p < 0.01; t-test). c The pronephros of 2-day old wild-type cldnb:GFP control zebrafish embryos rapidly regenerates after a laser-induced injury. The arrow points to the regenerated area at 24 h after the injury. The arrowhead points to the cloaca. The pronephros is outlined with dashed lines (scale bar, 100 µm). d Magnification of the regenerating region depicted in c (scale bar, 20 µm). e cxcl12a (−/−) zebrafish embryos fail to regenerate and the pronephric tubule remains discontinued. The arrow points to the gap in the tubule. The pronephros is outlined with discontinued lines. The arrowhead points to the cloaca. Note the dilation of the anterior duct due to ongoing filtration (scale bar, 100 µm). f Magnification of the region that failed to regenerate depicted in d (scale bar, 20 µm). g In some cases, cxcl12a mutant embryos showed aberrant regeneration and formed dorsal pouches. The arrow points to the abnormally regenerated tubule. The pronephros is outlined with discontinued lines. The arrowhead points to the cloaca (scale bar, 100 µm). h Magnification of the abnormally regenerated region depicted in e (scale bar, 20 µm). i cxcr4b mutant zebrafish embryos failed to re-establish the tubular patency similar to cxcl12a mutant embryos. The arrow points to the gap in the tubule. The pronephros is outlined with discontinued lines. The arrowhead points to the cloaca (scale bar, 100 µm). j Magnification of the region that failed to regenerate depicted in f (scale bar, 20 µm)
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