Martinez C B R, Nagae M Y, Zaia C T B V, Zaia D A M
Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina, C.P 6001, CEP 86051-990, Londrina, Paraná, Brazil.
Braz J Biol. 2004 Nov;64(4):797-807. doi: 10.1590/s1519-69842004000500009. Epub 2005 Mar 2.
The present study investigated lead effects on gill morphology, hematocrit, blood sodium, glucose, lipids, protein, and cholesterol of Prochilodus lineatus exposed to two sublethal lead concentrations for 96 h. Preliminary series of short-term static toxicity tests were run to determine LC50 (96 h) of lead in P. lineatus, which was 95 mg Pb.L-1. Therefore, lead concentrations tested in the sublethal experiments were 24 and 71 mg Pb.L-1, which correspond to 25% and 75% of the LC50 (96 h), respectively. Gills of P. lineatus exposed to both lead concentrations during 96 h presented a higher occurrence of histopathological lesions such as epithelial lifting, hyperplasia, and lamellar aneurism. P. lineatus did not show significant alterations in hematocrit during exposure to both lead concentrations. Fish exposed to the highest lead concentration showed a significant decrease in Na+ plasma concentration after 48 h, possibly reflecting a sodium influx rate decrease. P. lineatus exposed to both lead concentrations presented a "classical general adaptation syndrome to stress", as hyperglycemia associated with lowered lipids and proteins was reported. Stress-response magnitude was dose-dependent. While the response to the lowest lead concentration might represent adaptation, the highest concentration seems to characterize exhaustion.
本研究调查了两种亚致死铅浓度暴露96小时对条纹锯脂鲤鳃形态、血细胞比容、血钠、葡萄糖、脂质、蛋白质和胆固醇的影响。进行了一系列初步的短期静态毒性试验，以确定条纹锯脂鲤中铅的LC50（96小时），其为95 mg Pb.L-1。因此，在亚致死实验中测试的铅浓度分别为24和71 mg Pb.L-1，分别相当于LC50（96小时）的25%和75%。在96小时内暴露于两种铅浓度下的条纹锯脂鲤的鳃出现了更高发生率的组织病理学损伤，如上皮隆起、增生和片状动脉瘤。条纹锯脂鲤在暴露于两种铅浓度期间血细胞比容没有显著变化。暴露于最高铅浓度的鱼在48小时后血浆Na+浓度显著降低，这可能反映了钠流入速率的降低。暴露于两种铅浓度下的条纹锯脂鲤表现出“经典的应激一般适应综合征”，因为报告了与脂质和蛋白质降低相关的高血糖。应激反应程度呈剂量依赖性。虽然对最低铅浓度的反应可能代表适应，但最高浓度似乎表明出现了衰竭。
