含微囊藻毒素的蓝藻水华提取物对小鼠抗氧化酶的毒性作用

在世界范围内发生的富含营养的废水中生长蓝藻水华已经造成了严重的水污染。已有报道显示水华中的有毒成分是一类单环七肽微囊藻毒素,它们对人和家畜有严重的毒害作用,本文所使用的蓝藻水华采集于我国的太湖地区。我们采用三个亚致死计量(16、32、64 mg冻干藻细胞/kg体重,相当于4.97、9.94、19.88μg藻毒素/kg体重)的蓝藻水华提取物(CBE),分析它们对小鼠肝脏抗氧化酶的影响。经过连续14d每天腹腔注射CBE,小鼠分别在第3、5、7、9、11、13、15天处死并检测三种主要的抗氧化酶:超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽巯基转移酶(GST)的活性。SOD和CAT的活性均呈现了抑制效应,GST的活性也发生了明显的变化。为了进一步确定过氧化的程度,我们又通过检测丙二醛的含量分析了脂质过氧化的程度。经过14d CBE处理后脂质过氧化表现出了明显的浓度依赖性的上升趋势。我们的结果表明,CBE对小鼠的抗氧化酶有严重毒害作用,并且能够引起脂质的过氧化。

Toxic effects of cyanobacteria bloom extract containing microcystins on antioxidant enzymes in mice

Cyanobacteria blooms that appear in eutrophic freshwaters around the world are contaminating water seriously. The toxic compound microcystins (MCs), a family of monocyclic hepta-peptide, generated by cyanobacteria blooms have been reported to have harmful effects on human being and domestic animals. In this paper, we collected cyanobacteria blooms from Taihu Lake, China and employed three sublethal dosages of cyanobacteria bloom extract (CBE) (16, 32 and 64 mg lyophilized algae cells/kg body weight, with contents of 4.97, 9.94 and 19.88 μg MCs equivalents/kg body weight) to assay its effects on the antioxidant i.p. injection for 14 days and were sacrificed on day 3, 5, 7, 9, 11, 13 and 15. Three main antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GTS) were examined. Inhibition effects of CBE on SOD and CAT activities were presented. Obvious changes of GST activity were also observed. To further determine the degree of peroxidation induced by CBE, the level of lipid peroxidation was analyzed by testing malondialdehyde (MDA) concentration. A significant dose-dependent increase of MDA level was found after 14 days of CBE exposure. Our results showed that CBE possessed the deleterious effects on antioxidant enzymes and caused the increase of lipid peroxidation level in mice's liver.