Lithobates catesbeianus tadpoles were exposed to 1 μg L⁻¹ of zinc (Zn), copper (Cu) and cadmium (Cd) alone or combined (1:1 and 1:1:1) for 2 and 16 days. Results showed a significant increase in the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities in the liver, kidney and muscle (except for GPx) in the groups exposed to metal either alone or co-exposed after 2 days compared to the control. After 16 days, SOD, CAT and GST activities decreased significantly in the liver and kidney and GPx activity increased in the liver. Reduced glutathione (GSH) increased in the liver and kidney following combined exposure and decreased after 2 days of metal exposure in the muscle. There were significant increases in lipid hydroperoxide (LPO) levels in the liver, kidney and muscle (2 and 16 days), with the highest levels after metal co-exposure. Cholinesterase (ChE) activity increased significantly in the brain after 2 days of exposure but decreased in the brain (16 days) and muscle (2 days) after exposure to metals, alone and combined. The current study highlighted that the antioxidant system of L. catesbeianus was sensitive to metals and specially to the co-exposure of the three metals, despite presenting differences in the response among tissues. In addition, tadpoles were sensitive at both periods of exposure, but in different modes with stress response (activation, up-regulation) at 2 days and oppression (down-regulation) at 16 days.

岩藻Catesbeianus were暴露于1μgL ^-1单独或组合（1：1和1：1：1）的锌（Zn），铜（Cu）和镉（Cd）进行2天和16天。结果显示，在暴露于金属的组中，肝脏，肾脏和肌肉（GPx除外）中的超氧化物歧化酶（SOD），过氧化氢酶（CAT），谷胱甘肽过氧化物酶（GPx）和谷胱甘肽S-转移酶（GST）活性显着增加。与对照组相比，在2天后单独或共同暴露。16天后，肝脏和肾脏中的SOD，CAT和GST活性显着降低，肝脏中的GPx活性升高。减少的谷胱甘肽（GSH）在联合暴露后在肝脏和肾脏中增加，而在肌肉中暴露2天后减少。肝脏，肾脏和肌肉中的脂质过氧化氢（LPO）水平显着增加（2天和16天），金属共同暴露后的水平最高。单独和联合暴露后2天，胆碱酯酶（ChE）活性在大脑中显着增加，但在大脑（16天）和肌肉（2天）中降低。目前的研究强调，尽管在组织之间的反应存在差异，但L. catesbeianus对金属特别是对三种金属的共同暴露敏感。另外，t在两个暴露时期都敏感，但是在不同的方式下，2的反应（激活，上调）在第2天，and的反应（下调）在16天。