Abstract：
There is a growing concern regarding the adverse risks exposure to cylindrospermopsin (CYN) might exert on animals and humans. However, data regarding the toxicity of this cyanotoxin to neotropical fish species are scarce. Using the fish species Poecilia reticulata, the influence of CYN concentrations equal to and above the tolerable for drinking water may produce on liver was determined by assessing biomarkers of antioxidant defense mechanisms and correlated to qualitative and semiquantitative histopathological observations. Adult females were exposed to 0.0 (Control); 0.5, 1 and 1.5 μg/L pure CYN for 24 or 96 hr, in triplicate. Subsequently the livers were extracted for biochemical assays and histopathological evaluation. Catalase (CAT) activity was significantly increased only by 1.5 μg/L CYN-treatment, at both exposure times. Glutathione -S-transferase (GST) activity presented a biphasic response for both exposure times. It was markedly decreased after exposure by 0.5 μg/L CYN treatment but significantly elevated by 1.5 μg/L CYN treatment. All CYN treatments produced histopathological alterations, as evidenced by hepatocyte cords degeneration, steatosis, inflammatory infiltration, melanomacrophage centers, vessel congestion, and areas with necrosis. Further, an IORG >35 was achieved for all treatments, indicative of the presence of severe histological alterations in P. reticulata hepatic parenchyma and stroma. Taken together, data demonstrated evidence that CYN-induced hepatotoxicity in P. reticulata appears to be associated with an imbalance of antioxidant defense mechanisms accompanied by histopathological liver alterations. It is worthy to note that exposure to low environmentally-relevant CYN concentrations might constitute a significant risk to health of aquatic organisms.
摘要：
人们越来越担心暴露于cylindrospermopsin（CYN）可能对动物和人类产生的不利风险。然而,有关这种蓝藻毒素对新热带鱼类的毒性的数据很少。使用鱼种Poeciliareticulata，CYN浓度等于或高于饮用水可能产生的耐受水平对肝脏的影响是通过评估抗氧化防御机制的生物标志物来确定的,并与定性和半定量组织病理学观察相关联.成年雌性暴露于0.0（对照）；0.5、1和1.5μg/L纯CYN24或96小时，一式三份。随后提取肝脏用于生化测定和组织病理学评估。过氧化氢酶（CAT）活性仅通过1.5μg/LCYN处理显着增加，在两个曝光时间。谷胱甘肽-S-转移酶（GST）活性在两个暴露时间均呈现双相反应。暴露于0.5μg/LCYN处理后显着降低，但暴露于1.5μg/LCYN处理后显着升高。所有CYN治疗均产生组织病理学改变，肝细胞索变性证明了这一点，脂肪变性,炎性浸润,黑素营养中心，船舶拥堵，和坏死区域。Further,所有治疗均达到IORG>35，提示存在严重的组织学改变。一起来看,数据表明,CYN诱导的网状假单胞菌肝毒性似乎与抗氧化防御机制失衡相关,并伴有组织病理学肝脏改变.值得注意的是，暴露于与环境相关的低CYN浓度可能对水生生物的健康构成重大风险。
