低剂量微囊藻毒素MC-LR诱导罗氏沼虾肝胰腺损伤及凋亡

Low-dose Microcystins MC-LR Induced Hepatopancreas Injury and Apoptosis in Macrobrachium rosenbergii

微囊藻毒素(microcystins, MCs)是由水华蓝藻释放出来的一种有生物活性的环庚肽化合物,具有较强的肝毒性,MC-LR是其分布最广的和毒性最强的一个亚型。罗氏沼虾(Macrobrachium rosenbergii)是我国比较重要的一个水产养殖品种,但由于养殖水体富营养化程度比较严重,常常爆发蓝藻水华,给其健康养殖带来较大的威胁,但是关于MCs对罗氏沼虾的毒性机制研究的报道较少。因此,使用环境相关浓度的MC-LR(0.5和5μg·L^-1)处理罗氏沼虾1、2和3周,通过组织学观察、免疫组化定位、氧化应激指标测定以及荧光定量PCR技术探究养殖水体中常见浓度MCs对罗氏沼虾的毒害效应及潜在机制。研究结果表明,较高环境相关浓度(5μg·L^-1)的MCs会在罗氏沼虾肝胰腺中显著富集,诱导氧化应激,破坏肝胰腺的形态和结构,并且破坏作用随暴露时间延长而加剧,并发生细胞凋亡。而较低浓度的MCs(0.5μg·L^-1)对肝胰腺的影响相对较小,但是依然会诱导罗氏沼虾肝胰腺氧化应激,并且在长时间作用下也会给肝胰腺组织带来损伤。上述研究结果证明,环境相关浓度的MCs对罗氏沼虾也有一定的毒害作用,并且毒害作用呈剂量与时间依赖效应。

Microcystins(MCs)are biologically active cyclic heptapeptide compounds,which released from cyanobacteria and widely distributed hepatotoxin.Macrobrachium rosenbergii is an important aquaculture species in China.However,due to the serious eutrophication of aquaculture waters,cyanobacteria blooms often occur,which brings greater threaten to their healthy farming.But there were few studies focused on the toxicity mechanism of MCs on M.rosenbergii.In the present study,M.rosenbergii were exposed to environmentally relevant concentra-tions of MC-LR(0.5 and 5μg·L^-1)for 1,2 and 3 weeks.Histological observation,immunohistochemical localization,oxidative stress index determination and real-time PCR were applied to explore the toxic effects and potential mechanisms of MCs on M.rosenbergii.The results showed that environmentally relevant high concentrations(5μg·L^-1)MCs were significantly enriched in the hepatopancreas of M.rosenbergii,and could induce oxidative stress,disrupt the morphology and structure of the hepatopancreas.After long time exposure,the destruction was aggravated and apoptosis was occurred.However,the low concentration of MCs(0.5μg·L^-1)showed a less influence on hepatopancreas,but it still induced oxidative stress and caused damage to hepatopancreas tissue with prolonged exposure duration.These results demonstrate that environmentally relevant concentrations of MCs also have a certain toxic effect on M.rosenbergii,and the toxic effect is dose-and time-dependent.