College of Agriculture and Biotechnology, Hunan University of Humanities, Science and Technology, Loudi 417000, Hunan, China.
College of Agriculture and Biotechnology, Hunan University of Humanities, Science and Technology, Loudi 417000, Hunan, China.
Aquat Toxicol. 2020 Dec;229:105671. doi: 10.1016/j.aquatox.2020.105671. Epub 2020 Nov 2.
In natural ecosystems, living organisms are always subjected to a mixture of multiple heavy metals exposure, yet it is more common to study the effect of individual, rather than combined exposure. This study assessed the impacts of single or combined exposure to Cr and Cu on embryonic development, oxidative stress, lipid metabolism and apoptosis in the early development of Bufo gargarizans embryos. The total length, development stage and malformations of embryos were measured, and the mRNA expression of genes related to oxidative stress, lipid metabolism and apoptosis at Gs 18 and Gs 22 were determined by RT-qPCR. The results showed that all treatments significantly reduced the total length of embryos, delayed the stage of embryonic development and increased the proportion of malformed embryos. The Cr-Cu mixture treatment showed the greatest suppression of embryonic development and induced the highest rate of embryo malformation, compared to individual Cr and Cu treatments. In addition, the expression levels of oxidative stress genes (HSP90, SOD and GPx) and fatty acid β-oxidation-related genes (ACOXL, ECHS1 and SCP) showed an up-regulated trend in treatments compared to control groups. Conversely, the lipid synthesis-related mRNA gene expressions (KAR, TECR, ACSL3 and ACSL4) were down-regulated. Among them, the Cr-Cu mixture had the greatest impact on lipid metabolism gene expression. The treatments showed significant effects on the expression of apoptosis genes (Bcl-1 and Bax), with Bcl-1 mRNA expression increasing and Bax mRNA expression decreasing. These results indicated that exposure to individual Cr, Cu and a Cr-Cu mixture can lead to oxidative stress, disrupt lipid metabolism and promote apoptosis, and the Cr-Cu mixture could cause more serious negative effects on B. gargarizans embryos than Cr or Cu individually.
在自然生态系统中，生物体总是受到多种重金属混合暴露的影响，但研究单一或联合暴露的影响更为常见。本研究评估了单一或联合暴露于铬（Cr）和铜（Cu）对泽蛙胚胎早期发育、氧化应激、脂质代谢和细胞凋亡的影响。测量了胚胎的全长、发育阶段和畸形率，并通过 RT-qPCR 测定了 Gs18 和 Gs22 时与氧化应激、脂质代谢和细胞凋亡相关的基因的 mRNA 表达。结果表明，所有处理均显著降低了胚胎全长，延迟了胚胎发育阶段，增加了畸形胚胎的比例。与单独的 Cr 和 Cu 处理相比，Cr-Cu 混合物处理对胚胎发育的抑制作用最大，并诱导了最高的胚胎畸形率。此外，与对照组相比，氧化应激基因（HSP90、SOD 和 GPx）和脂肪酸β-氧化相关基因（ACOXL、ECHS1 和 SCP）的表达水平呈上调趋势。相反，脂质合成相关 mRNA 基因的表达（KAR、TECR、ACSL3 和 ACSL4）下调。其中，Cr-Cu 混合物对脂质代谢基因表达的影响最大。这些处理对凋亡基因（Bcl-1 和 Bax）的表达有显著影响，Bcl-1 mRNA 表达增加，Bax mRNA 表达减少。这些结果表明，单独暴露于 Cr、Cu 和 Cr-Cu 混合物均可导致氧化应激、破坏脂质代谢并促进细胞凋亡，且 Cr-Cu 混合物对泽蛙胚胎的负面影响可能比单独暴露于 Cr 或 Cu 更为严重。
