Study on the dose-effect relationship of tritium water in the early growth and development of zebrafish

Objective To study the effect of tritium water radiation dose on zebrafish at early developmental stages and integration with biological effects for the preliminary observation of dose–effect relationships.

Methods The real experimental conditions were simulated, the physical conditions were modeled, and the absorbed dose rates were calculated for 24 hours post fertilization (hpf）embryos and 96 hpf larvae in three different concentrations of tritium water: 3.7×10³, 3.7×10⁴, and 3.7×10⁵ Bq/ml. The embryos or larvae turnover frequency and heart rate of 24 and 96 hpf were observed and compared with those of the control group. Comparisons between multiple groups were analyzed by one-way ANOVA, and differences between the control and treatment groups were compared for significance using the LSD-t test.

Results With the extension of development time, the absorbed dose of zebrafish increased in three different concentrations of tritiated water. 24 hpf embryos corresponding to dose rates of 2.15×10, 2.21×10², 2.55×10³ μGy/h; 96 hpf larvae corresponding to dose rates of 2.95×10, 3.03×10², 3.47×10³ μGy/h. Comparison with control group, the results of 24 hpf embryo flipping showed that the significantly fewer embryos turned over in the tritium water-stained group whith 3.7×10³ Bq/ml( t=3.94, P＜0.001); and 96 hpf larvae heart rate changes significantly with tritium water concentration. Comparison with control group, the 3.7×10³ Bq/ml tritium water-treated group had a significant decrease in heart rate(t=2.86, P=0.01), while the 3.7×10⁵ Bq/ml tritium water-treated group had an increase in heart rate (t=−12.12, P<0.001).

Conclusion Significant changes in embryonic turnover at 24 hpf and heart rate of larvae at 96 hpf were observed with changes in absorbed dose rate.