Objective: To evaluate the safety of dianhydrogalactitol (DAG) in zebrafish embryos. Method: The 6 hours post fertilization (hpf)

normally developed zebrafish embryos were exposed to DAG solution in two different experimental groups (A and B). Group A was a low-dose concentration group:98.00

110.00

125.00

141.00

160.00 mg·L-1

while group B was a high-dose concentration group:661.00

871.00

1 148.00

1 514.00

and 1 995.00 mg·L-1. The corresponding blank controls were set for both groups. The DAG solution was refreshed every 24 h. Microscope was used to observe embryos development at different treating periods. Finally

the median lethal concentration (LC50)

median effect concentration (EC50)

therapeutic index (TI) and safety index (SI) were calculated. Result: Zebrafish heart rate of group B at 48 hpf was decreased with the increase of concentration of DAG solution. In addition

48

72

96 hpf hatchabilities showed different trends at different observation time points (48

72

96 hpf). Difference was statistically significant compared with controls in both groups (P<0.01). Deformity rate and mortality rate of zebrafish embryos were increased with the increasing concentration of DAG solution and extended medication time (P<0.01). The LC50 was 1 851.33 mg·L-1

EC50 of 184.50 mg·L-1

TI of 10.03 mg·L-1

and SI of 1.59 mg·L-1at 72 hpf. LC50 at 96 hpf was 1 071.96 mg·L-1

EC50 of 74.76 mg·L-1

TI of 14.34 mg·L-1

and SI of 2.94 mg·L-1. LC50 at 6 dpf was 133.12 mg·L-1. Conclusion: There is a significant dose-dependent relationship between the concentration of DAG solution and the toxicity in zebrafish embryos development. There is also a significant dose-dependent relationship between the exposure time and the toxicity. In conclusion DAG's safety evaluation index is relatively high.