Fig. 4

Fig. 4

Expression of osteoblast differentiation markers in 6-dpf zebrafish larvae exposed to ethanolic extracts of Skeletonema costatum (SKLT) and Tetraselmis striata CTP4 (CTP4). Representative images of Arunx2-positive osteochondroprogenitor cells, Csp7-positive immature osteoblasts, and Eoc1-positive mature osteoblasts, and quantification of fluorescence signal area for runx2 (B), sp7 (D), and oc1 (E) positive cells. Normality was tested though Anderson–Darling test (p < 0.05). For fluorescence signals, differences were tested through one-way ANOVA or Kruskal–Wallis test. Asterisks indicate p < 0.0021 (**), p < 0.0002 (***) and p < 0.0001 (****). For gene expression, differences were tested through a non-parametric Kruskal–Wallis test, followed by a Dunn’s multiple comparison test (significant P values are reported above each treatment)