Laboratory of Immunology Applied to Aquaculture, Department of Cell Biology, Embryology and Genetics, Biological Sciences Center, Federal University of Santa Catarina, 88040-900, Florianópolis, SC, Brazil.
Laboratory of Cell Defense, Department of Biochemistry, Biological Sciences Center, Federal University of Santa Catarina, 88040-900, Florianópolis, SC, Brazil.
Mar Drugs. 2012 Mar;10(3):583-597. doi: 10.3390/md10030583. Epub 2012 Mar 5.
Hemocytes mediate a series of immune reactions essential for bivalve survival in the environment, however, the impact of harmful algal species and their associated phycotoxins upon bivalve immune system is under debate. To better understand the possible toxic effects of these toxins, Crassostrea gigas hemocytes were exposed to brevetoxin (PbTx-2). Hemocyte viability, monitored through the neutral red retention and MTT reduction assays, and apoptosis (Hoechst staining) remained unchanged during 12 h of exposure to PbTx-2 in concentrations up to 1000 µg/L. Despite cell viability and apoptosis remained stable, hemocytes incubated for 4 h with 1000 µg/L of PbTx-2 revealed higher expression levels of Hsp70 (p < 0.01) and CYP356A1 (p < 0.05) transcripts and a tendency to increase FABP expression, as evaluated by Real-Time quantitative PCR. The expression of other studied genes (BPI, IL-17, GSTO, EcSOD, Prx6, SOD and GPx) remained unchanged. The results suggest that the absence of cytotoxic effects of PbTx-2 in Crassostrea gigas hemocytes, even at high concentrations, allow early defense responses to be produced by activating protective mechanisms associated to detoxification (CYP356A1 and possibly FABP) and stress (Hsp70), but not to immune or to antioxidant (BPI, IL-17, EcSOD, Prx6, GPx and SOD) related genes.
血细胞介导了一系列对贝类在环境中生存至关重要的免疫反应，然而，关于有害藻类物种及其相关藻毒素对贝类免疫系统的影响仍存在争议。为了更好地了解这些毒素的可能毒性作用，采用血细胞暴露于短裸甲藻毒素（PbTx-2）的方法，利用中性红保留和 MTT 还原试验监测血细胞活力，以及通过 Hoechst 染色观察细胞凋亡，结果表明在浓度高达 1000μg/L 的 PbTx-2 暴露 12 小时内，血细胞活力和细胞凋亡没有变化。尽管细胞活力和细胞凋亡保持稳定，但孵育 4 小时后用 1000μg/L 的 PbTx-2 处理的血细胞，其 Hsp70（p < 0.01）和 CYP356A1（p < 0.05）转录本的表达水平更高，并显示出 FABP 表达增加的趋势，这是通过实时定量 PCR 评估的。其他研究基因（BPI、IL-17、GSTO、EcSOD、Prx6、SOD 和 GPx）的表达保持不变。结果表明，即使在高浓度下，PbTx-2 对太平洋牡蛎血细胞没有细胞毒性作用，这允许通过激活与解毒（CYP356A1 和可能的 FABP）和应激（Hsp70）相关的保护机制来产生早期防御反应，但不会影响与免疫或抗氧化（BPI、IL-17、EcSOD、Prx6、GPx 和 SOD）相关的基因。
