Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture of P.R.C., Fishery College, Huazhong Agricultural University, Wuhan 430070, China; Freshwater Aquaculture Collaborative Innovative Centre of Hubei Province, Wuhan 430070, China.
Aquat Toxicol. 2013 Oct 15;142-143:380-6. doi: 10.1016/j.aquatox.2013.09.011. Epub 2013 Sep 16.
The present study was conducted to investigate the effect of waterborne cadmium (Cd) exposure on lipid metabolism in liver and muscle of juvenile yellow catfish Pelteobagrus fulvidraco. Yellow catfish were exposed to 0 (control), 0.49 and 0.95 mg Cd/l, respectively, for 6 weeks, the lipid deposition, Cd accumulation, the activities and expression level of several enzymes as well as the mRNA expression of transcription factors involved in lipid metabolism in liver and muscle were determined. Waterborne Cd exposure reduced growth performance, but increased Cd accumulation in liver and muscle. In liver, lipid content, the activities and the mRNA expression of lipogenic enzymes (6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), fatty acid synthetase (FAS)) and lipoprotein lipase (LPL) activity increased with increasing waterborne Cd concentrations. However, the mRNA expressions of LPL and peroxisome proliferators-activated receptor (PPAR) α were down-regulated by Cd exposure. Carnitine palmitoyltransferase 1 (CPT1) activity as well as the mRNA expressions of CPT1 and PPARγ showed no significant differences among the treatments. In muscle, lipid contents showed no significant differences among the treatments. The mRNA expression of 6PGD, FAS, CPT1, LPL, PPARα and PPARγ were down-regulated by Cd exposure. Thus, our study indicated that Cd triggered hepatic lipid accumulation through the improvement of lipogenesis, and that lipid homeostasis in muscle was probably conducted by the down-regulation of both lipogenesis and lipolysis. Different variation patterns of lipid metabolism to waterborne Cd exposure indicated the tissue-specific regulatory effect of lipid metabolism under waterborne Cd exposure. To our knowledge, the present study provides, for the first time, evidence that waterborne chronic Cd exposure can disturb the normal processes of lipid metabolism at both the enzymatic and molecular levels, and in two tissues (the liver and muscle).
本研究旨在探讨水相镉（Cd）暴露对黄颡鱼（Pelteobagrus fulvidraco）幼鱼肝脏和肌肉脂质代谢的影响。将黄颡鱼分别暴露于 0（对照）、0.49 和 0.95mg/L Cd 中 6 周，测定肝脏和肌肉中脂质沉积、Cd 积累、几种酶的活性和表达水平，以及参与脂质代谢的转录因子的 mRNA 表达。水相 Cd 暴露降低了生长性能，但增加了肝脏和肌肉中的 Cd 积累。在肝脏中，随着水相 Cd 浓度的增加，脂质含量、生脂酶（6-磷酸葡萄糖酸脱氢酶（6PGD）、葡萄糖-6-磷酸脱氢酶（G6PD）、脂肪酸合成酶（FAS））和脂蛋白脂肪酶（LPL）活性以及 LPL 和过氧化物酶体增殖物激活受体（PPAR）α的 mRNA 表达增加。然而，Cd 暴露下调了 LPL 和 PPARα 的 mRNA 表达。肉碱棕榈酰转移酶 1（CPT1）活性以及 CPT1 和 PPARγ 的 mRNA 表达在各处理组之间无显著差异。肌肉中，各处理组之间的脂质含量无显著差异。6PGD、FAS、CPT1、LPL、PPARα 和 PPARγ 的 mRNA 表达均受 Cd 暴露下调。因此，本研究表明，Cd 通过改善生脂作用引发肝脏脂质积累，而肌肉中的脂质稳态可能是通过下调生脂和脂解作用来实现的。脂质代谢对水相 Cd 暴露的不同变化模式表明，水相 Cd 暴露下脂质代谢具有组织特异性的调节作用。据我们所知，本研究首次提供了证据，证明水相慢性 Cd 暴露可以在两个组织（肝脏和肌肉）的酶和分子水平上扰乱脂质代谢的正常过程。
