低剂量氯氟氰菊酯对斑马鱼胚胎运动行为的影响

目的：研究低剂量氯氟氰菊酯对斑马鱼胚胎运动行为的影响。方法：用0、10、20、40、80、100 µg/L的氯氟氰菊酯对斑马鱼胚胎进行处理，进行畸形表型及浓度效应分析。研究0、2.5、5、10 µg/L的低剂量氯氟氰菊酯对斑马鱼胚胎自主运动、接触反应、自由泳动等运动行为的影响。结果：氯氟氰菊酯暴毒斑马鱼胚胎的主要畸形表型为心包囊肿大、脊柱和尾部弯曲、卵黄囊肿大等。与对照组比，20 µg/L及以上浓度暴露下斑马鱼胚胎的畸形率显著提高（P＜0.05），而10 µg/L氯氟氰菊酯对斑马鱼胚胎无明显致畸效应。氯氟氰菊酯在胚胎受精后120 h（120 hpf）的半数致畸浓度（EC50）为38.61 µg/L。运动行为检测结果显示，2.5 µg/L暴露下斑马鱼胚胎的自主运动频率在19、21和22 hpf时显著升高（P＜0.05），10 µg/L氯氟氰菊酯暴露下胚胎的自主运动频率在20和21 hpf时显著下降（P＜0.05），且峰值由21 hpf延迟到22 hpf；5、10 µg/L组胚胎在27和48 hpf时对接触反应的运动距离呈显著下降（P＜0.05）；10 µg/L氯氟氰菊酯显著降低了仔鱼的自由泳动速度（P＜0.01）。结论：氯氟氰菊酯对斑马鱼胚胎有严重的致畸效应，且呈现剂量依赖性。对斑马鱼胚胎无明显致畸效应的低剂量氯氟氰菊酯即可显著影响其自主运动、接触反应、自由泳动等发育早期的运动行为。

Effect of low-dose cyhalothrin on motor behavior in zebrafish embryos

Objective: To study the effects of low-dose cyhalothrin on motor behavior in zebrafish embryos. Methods: The dose-response effects and malformation phenotype were evaluated by observing zebrafish embryos exposed to different concentrations of 0, 10, 20, 40, 80, 100 µg/L cyhalothrin solutions. The impact of low-dose of 0, 2.5, 5, 10 µg/L cyhalothrin on several motor behaviors in zebrafish embryos was then explored, including embryonic spontaneous movement, touch response and larval swimming speed. Results: The predominant malformation phenotypes observed in surviving embryos were edema of pericardialsac, bent spine, curved tail and yolk sac edema. Compared with the control group, zebrafish embryos exposed to 20 µg/L and above concentrations showed significantly increased malformation rate (P<0.05), while 10 µg/L cyhalothrin exhibited no influence on embryonic development. Cyhalothrin concentration that led to 50% malformations (EC50) of the embryos at 120 hours post fertilization (hpf) was 38.61 µg/L. A series of motor behavior tests revealed that embryos exposed to 2.5 µg/L cyhalothrin displayed remarkably elevated spontaneous movement frequency at 19, 21 and 22 hpf (P<0.05), while this frequency was decreased in embryos treated with 10 µg/L cyhalothrin at 20-21 hpf (P<0.05); besides, 5, 10 µg/L cyhalothrin exposure induced markedly reduction of touch response movement in zebrafish embryos at both 27 and 48 hpf (P<0.05); moreover, 10 µg/L cyhalothrin reduced larval swimming movement speed at 120 hpf (P<0.01). Conclusion: Cyhalothrin causes severe embryonic toxicity in a dose-dependent manner. Low dose of cyhalothrin exposure which shows no effect on embryonic development significantly alters several motor behaviors at early life stage.