Hexavalent Chromium Inhibited Zebrafish Embryo Development by Altering Apoptosis- and Antioxidant-Related Genes

This study aimed to assess the effects of hexavalent chromium on zebrafish (Danio rerio) embryo development. The zebrafish embryos were treated with solutions containing chromium at different concentrations (0.1, 1, 3.125, 6.25, 12.5, 50, and 100 & mu;g/mL). The development of zebrafish embryos was estimated by the determination of survival rate, heart rate, and the measurement of larvae body length. Real time RT-PCR and Western blot were performed to assess the expression of apoptosis- and antioxidant-related genes. The results showed that the reduced survival rate of zebrafish embryos and larvae was associated with an increase in chromium concentration. The exposure of higher concentrations resulted in a decrease in body length of zebrafish larvae. In addition, a marked increase in heart rate was observed in the zebrafish larvae under chromium treatment, especially at high concentrations. The real-time RT-PCR analysis showed that the transcript expressions for cell-cycle-related genes (cdk4 and cdk6) and antioxidant-related genes (sod1 and sod2) were downregulated in the zebrafish embryos treated with chromium. Western blot analysis revealed the upregulation of Caspase 3 and Bax, while a downregulation was observed in Bcl2. These results indicated that hexavalent chromium induced changes in zebrafish embryo development by altering apoptosis- and antioxidant-related genes.

Automated summary

The study aimed to evaluate the impact of hexavalent chromium on the development of zebrafish embryos. The embryos were exposed to different concentrations of chromium, and their survival rate, heart rate, and body length were measured. The expression of apoptosis- and antioxidant-related genes was analyzed using real-time RT-PCR and Western blot. The results showed that higher chromium concentrations led to decreased survival rate and body length, as well as increased heart rate in zebrafish larvae. The expression of cell-cycle-related and antioxidant-related genes was downregulated, while caspase 3 and Bax were upregulated, suggesting that hexavalent chromium altered zebrafish embryo development by affecting apoptosis- and antioxidant-related genes.