Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Rio Grande, RS, Brazil.
J Toxicol Environ Health A. 2012;75(16-17):1023-34. doi: 10.1080/15287394.2012.697813.
South American cyprinodontiform fish are potential candidates to be used as model biomarker species of exposure in environmental toxicology. The aim of this study was to identify molecular and biochemical biomarkers of pollution using Poecilia vivipara (Poecilidae) and Jenynsia multidentata (Anablepidae). Partial nucleotide sequences for cytochrome P-450 1A (CYP1A), a classical biomarker of exposure to organic contaminants in fish, were identified in P. vivipara and J. multidentata (approximately 650 nucleotides) using degenerated primers and polymerase chain reaction (PCR). These sequences shared approximately 90% identity in the predicted amino acid sequence with the corresponding CYP1A region of Fundulus heteroclitus. Real-time quantitative PCR (RT-qPCR) analysis confirmed that CYP1A transcription was markedly induced in the liver and gills of J. multidentata (approximately185-fold and 20-fold, respectively) and P. vivipara (122-fold and 739-fold, respectively) 24 h after exposure to 1 μM synthetic CYP1A inducer β-naphthoflavone (BNF). At 24 h after injection with 1 μg/g environmental carcinogenic contaminant benzo[a]pyrene (BaP), a decreased total antioxidant capacity against peroxyl radicals was observed both in liver of J. multidentata and gills of P. vivipara. BaP injection in both fish did not produce changes in lipid peroxide (thiobarbituric acid-reactive substances, TBARS) levels, suggesting an absence of an oxidative stress condition. The newly identified CYP1A may thus serve as general biomarker of exposure to organic contaminant in future studies using P. vivipara and J. multidentata. Data also indicate the importance of species-specific differences in biomarker responses in these South American cyprinodontiform fish, suggesting distinct resistance/susceptibility properties to polycyclic aromatic hydrocarbons.
南美脂鲤目鱼类是作为环境毒理学暴露模型生物标志物的潜在候选者。本研究的目的是使用胎生鱂鱼（胎生鱂科）和詹尼氏多齿脂鲤（脂鲤科）来识别污染的分子和生化生物标志物。使用简并引物和聚合酶链反应（PCR）从胎生鱂鱼和詹尼氏多齿脂鲤中鉴定了细胞色素 P-450 1A（CYP1A）的部分核苷酸序列，这是鱼类暴露于有机污染物的经典生物标志物（约 650 个核苷酸）。这些序列在预测的氨基酸序列中与金鲈（Fundulus heteroclitus）的相应 CYP1A 区域具有约 90%的同一性。实时定量 PCR（RT-qPCR）分析证实，暴露于 1 μM 合成 CYP1A 诱导剂β-萘黄酮（BNF）后，詹尼氏多齿脂鲤的肝脏和鳃中 CYP1A 的转录明显诱导（分别为约 185 倍和 20 倍），胎生鱂鱼（分别为 122 倍和 739 倍）。在注射 1μg/g 环境致癌污染物苯并[a]芘（BaP）24 小时后，詹尼氏多齿脂鲤肝脏和胎生鱂鱼鳃中的总抗氧化能力对过氧自由基的降低。在这两种鱼中注射 BaP 均未导致脂质过氧化物（硫代巴比妥酸反应物质，TBARS）水平发生变化，表明不存在氧化应激状态。新鉴定的 CYP1A 因此可以作为未来使用胎生鱂鱼和詹尼氏多齿脂鲤的有机污染物暴露的一般生物标志物。数据还表明，这些南美的脂鲤目鱼类在生物标志物反应方面存在种间差异的重要性，表明它们对多环芳烃具有不同的抗性/敏感性。
