Developmental toxicity of trichloroisocyanuric acid on zebrafish embryos and larvae / 中国药理学与毒理学杂志

ABSTRACT

OBJECTIVE To investigate the developmental toxicity of a new disinfectant trichloroiso-cyanuric acid (TCCA) on zebrafish embryos and larvae. METHODS Zebrafish embryos of 2 h post fertilization (hpf) were exposed to TCCA①The embryos were exposed to a culture medium containing TCCA 0, 50, 100, 150, 200, 250 and 300 mg·L-1 for 48 h before 50%lethal concentration (LC50) was calcu-lated. ② The embryos were exposed to a culture medium containing TCCA 0, 10.4, 20.8 and 41.7 mg · L-1 for 96 h. The mortality, malformation rate and heart rate of embryos and larvae were measured at 48, 72 and 96 h after TCCA exposure. The expression of superoxide dismutase (SOD) was detected at 2, 4 and 6 h after TCCA exposure. The pathological changes in the head of zebrafish larvae were observed 7 d after exposure by HE staining. RESULTS LC50 of 48 h after TCCA exposure was 166.9 mg · L-1. Compared with normal control group, the mortality and malformation rate of zebrafish embryos were significantly increased (P<0.05) in TCCA 41.7 mg · L-1 group, but the heart rate was decreased significantly (P<0.05) in each dose of TCCA group at 96 h after TCCA exposure. At 72 h after TCCA exposure, the mortality rate of zebrafish embryos was significantly increased (P<0.05) in TCCA 41.7 mg·L-1 group, the malformation rate of zebrafish embryos was increased (P<0.05) and the heart rate of zebrafish embryos was decreased (P<0.05) in 20.8 and 41.7 mg · L-1 groups. At 48 h after TCCA exposure, the heart rate of zebrafish embryos was decreased significantly (P<0.05) in 41.7 mg · L-1 group. The SOD activity of zebrafish embryos in 20.8 and 41.7 mg · L-1 groups was significantly lower than that of control group (P<0.05). At 7 d after exposure, the brain and ocular space of larvae were enlarged and the ocular retina layers were not obvious in any dose of TCCA groups. CONCLUSION TCCA has toxic effect on zebrafish embryonic development, which can down-regulate SOD activity in the early developmental stage of embryos and damage the retina tissue of larvae.