TESTING OF DEXAMETHASONE TOXICITY TO CARDIOMETABOLIC AND MALFORMATION OF ZEBRAFISH (Danio rerio Hamilton, 1882) LARVAE

This study aims to evaluate the toxicity effects of dexamethasone on survival, hatching, cardiometabolic function, and the emergence of malformations in zebrafish larvae (Danio rerio), a vertebrate model organism. The study was conducted during the embryonic to early larval phase (0 – 96 hpf) using an in vivo  experimental design with  complete randomization, following the Zebrafish Embryo Toxicity Test (ZFET) approach, in accordance with OECD 236 guidelines. Zebrafish embryos were exposed to varying concentrations of dexamethasone (0.5,1, 3, and 7 ppm). The parameters observed included survival rate, hatching rate, cardiometabolic function, and changes in larval morphology. Data were analyzed using normality and homogeneity tests, followed by One-Way ANOVA with LSD post hoc tests and Two-Way ANOVA. The results showed that exposure to dexamethasone did not cause lethal toxicity in zebrafish larvae up to 96 hpf (P = 0.949), but significantly inhibited hatching at 48 hpf (P = 0.007) and 72 hpf (P = 0.032). Dexamethasone was also significant in lowering the larvae’s heart rate in a dose- and time-dependent manner (P < 0.001). The two-way ANOVA results further indicated that dose, exposure time, and their interaction had significant effects on cardiometabolic function (P < 0.001).