Key Laboratory of Tropical Island Ecology, Ministry of Education, Hainan key Laboratory of Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China.
Key Laboratory of Tropical Island Ecology, Ministry of Education, Hainan key Laboratory of Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, PR China.
Aquat Toxicol. 2021 Aug;237:105903. doi: 10.1016/j.aquatox.2021.105903. Epub 2021 Jun 25.
Ammonia is a major pollutant in the water environment, which could cause severe harm to aquatic organisms. To explore the pathological and physiological effects of ammonia in Chinese striped-necked turtles (Mauremys sinensis), the individuals (body mass: 218.26 ± 12.65 g) were divided into two groups: control group and ammonia exposed group (6.25 mM total ammonia), then the expression levels of signaling factors involved in the endoplasmic reticulum stress and apoptotic pathways were determined. The results showed that ammonia exposure up-regulated the transcriptional and protein levels of endoplasmic reticulum stress marker gene Bip. Meanwhile, the relative mRNA levels of key genes (PERK, ATF6, eIF2α, ATF4, IRE1α and XBP1) involved in unfolded protein response up-regulated, and the phosphorylation levels of PERK, eIF2α and IRE1α increased correspondingly. In addition, the protein and transcriptional levels of CHOP and JNK related to apoptotic pathway induced by unfolded protein reaction increased under ammonia exposure. Moreover, Bcl-2 mRNA expression levels and protein levels decreased, whereas BAX and caspase-3 showed an opposite trend, and the cleaved protein of caspase-3 appeared when the turtles in the elevated ammonia. Furthermore, the apoptotic cells in liver increased after ammonia exposure. These results suggested ammonia exposure induced endoplasmic reticulum stress, then activated unfolded protein response, followed by apoptosis in M. sinensis. The results will contribute to a better understanding of the toxicity mechanism of ammonia to aquatic turtles.
氨是水环境中的一种主要污染物，它会对水生生物造成严重的危害。为了研究氨对中华鳖（Mauremys sinensis）的病理和生理影响，将个体（体重：218.26±12.65g）分为对照组和氨暴露组（6.25mM 总氨），然后测定参与内质网应激和凋亡途径的信号因子的表达水平。结果表明，氨暴露上调了内质网应激标志物基因 Bip 的转录和蛋白水平。同时， unfolded protein response 相关关键基因（PERK、ATF6、eIF2α、ATF4、IRE1α 和 XBP1）的相对 mRNA 水平上调，PERK、eIF2α 和 IRE1α 的磷酸化水平相应增加。此外，在氨暴露下，与 unfolded protein response 诱导的凋亡途径相关的 CHOP 和 JNK 的蛋白和转录水平增加。此外，Bcl-2mRNA 表达水平和蛋白水平降低，而 BAX 和 caspase-3 则呈现相反的趋势，caspase-3 的裂解蛋白在氨升高时出现。此外，氨暴露后肝脏中的凋亡细胞增加。这些结果表明，氨暴露诱导内质网应激，继而激活 unfolded protein response，随后导致中华鳖发生凋亡。这些结果有助于更好地理解氨对水生龟类的毒性机制。
