Laboratorio de Ecotoxicología, Facultad de Bioquímica y Ciencias Biológicas (FBCB), Universidad Nacional del Litoral (UNL), Santa Fe, Argentina.
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
J Environ Sci Health B. 2021;56(1):41-53. doi: 10.1080/03601234.2020.1832410. Epub 2020 Oct 28.
Dexamethasone (DEX) is a glucocorticoid highly effective as an anti-inflammatory, immunosuppressant and decongestant drug. In the present study, a preliminary acute toxicity test was assayed in order to determinate DEX median-lethal, lowest-observed-effect and the no-observed-effect concentrations (LC, LOEC and NOEC, respectively) on the common toad embryos (). Also, morphological and histological abnormalities from five body larval regions, liver melanomacrophages (MM) and glutathione S-transferase (GST) activity were evaluated in the toad larvae to characterize the chronic sublethal effects of DEX (1-1,000 µg L). Results of the acute test showed that the LC of DEX at 96 h of exposure for the toad embryos (GS 18-20) was 10.720 mg L, and the LOEC was 1 µg L. In the chronic assay, the larval development and body length were significantly affected. DEX exposition also induced teratogenic effects. Most frequent external abnormalities observed in DEX-treated larvae included abdominal edema and swollen body, abnormal gut coiling and visceral congestion. Intestinal dysplasia was recurrent in cross-section of all DEX-treated larvae. Neural, conjunctive and renal epithelial cells were also affected. Significant increase in liver MM number and size, and GST activity levels were also registered in DEX treatments with respect to controls. The evaluation of a variety of biomarkers provided clear evidence of toad larvae sensitivity to DEX, and the ecotoxicological risk of these pharmaceuticals, commonly found in different water bodies worldwide on aquatic animals.
地塞米松（DEX）是一种高效的抗炎、免疫抑制和解充血药物。在本研究中，进行了初步的急性毒性试验，以确定 DEX 对普通蟾蜍胚胎（）的半数致死量、最低观察到的效应浓度和无观察到的效应浓度（LC、LOEC 和 NOEC）。此外，还评估了五个体节区域的幼虫形态和组织学异常，以及肝脏黑色素巨噬细胞（MM）和谷胱甘肽 S-转移酶（GST）活性，以表征 DEX 的慢性亚致死效应（1-1000μg L）。急性试验结果表明，DEX 在蟾蜍胚胎（GS 18-20）暴露 96 小时的 LC 为 10.720mg L，LOEC 为 1μg L。在慢性试验中，幼虫发育和体长受到显著影响。DEX 暴露还引起了致畸作用。在 DEX 处理的幼虫中观察到的最常见的外部异常包括腹部水肿和肿胀、肠道异常卷曲和内脏充血。在所有 DEX 处理的幼虫的横切面上，都出现了肠道发育不良。神经、连接组织和肾上皮细胞也受到影响。与对照组相比，DEX 处理还导致肝脏 MM 数量和大小以及 GST 活性水平显著增加。对各种生物标志物的评估提供了明确的证据，证明蟾蜍幼虫对 DEX 的敏感性，以及这些药物对水生动物的水生环境的生态毒性风险。
