metallothionein and decamethrin

The hazardous effects of pesticides on various metabolic pathways are a great problem for environmental health and should be well determined. In the present study, the authors treated rainbow trout with 0.6 μg/L deltamethrin for 28 days and 1.6 mg/L 2,2-dichlorovinyl dimethyl phosphate for 21 days. After this time period, the authors observed alterations in mRNA expression levels of MT-A, MT-B and CYP-1A. Chronic exposure to low levels of pesticides may have a more significant effect on fish populations than acute poisoning. While both pesticides caused a significant increase on mRNA levels of MT-A and CYP-1A, MT-B mRNA levels were increased significantly only upon deltamethin administration. The significant increase in mRNA levels of the corresponding genes may be considered as a defence mechanism in addition to the antioxidants against oxidative stress, as well as a detoxification mechanism against adverse effects of pesticides.

Topics: Animals; Cytochrome P-450 CYP1A1; Dichlorvos; Gene Expression; Gene Expression Profiling; Insecticides; Metallothionein; Nitriles; Oncorhynchus mykiss; Pyrethrins; Real-Time Polymerase Chain Reaction; RNA, Messenger; Toxicity Tests, Chronic

Metallothioneins (MT) are widely utilized to identify specific responses to heavy metal pollution. In addition, there is evidence demonstrating that in vertebrates MT synthesis is stimulated by different endogenous and exogenous agents in particular compounds leading to production of ROS. Also, cytochrome P450 1A can enhance the generation of ROS. On this basis, MT and CYP 1A induction can be considered as biomarkers of oxidative stress. In the current study, we examined the influences of pesticide administration on the expression of MT-A, MT-B and CYP 1A. For this purpose, we produced muscle metallothionein-A, metallothionein-B and cytochrome P450 1A cDNAs and used quantitative RT-PCR to assay mRNAs in rainbow trout exposed to acute and long-term deltamethrin administration. We observed that deltamethrin exposure significantly (p<0.05) increased the expression levels of Cyp1A, MT-A and MT-B in a time dependent manner. Results of our study contributes to the identification of inducers of such biomarkers in addition to well known agents.

Topics: Animals; Cytochrome P-450 Enzyme System; Insecticides; Metallothionein; Muscles; Nitriles; Oncorhynchus mykiss; Pyrethrins; RNA, Messenger; Up-Regulation

The modulatory effect of cadmium pretreatment (0.2 mg/kg b.w. i.p.) on deltamethrin-induced oxidative stress and alterations of antioxidants was studied in freshwater fish Channa punctata Bloch. Lipid peroxidation (LPO) was measured as one of the indicators of oxidative stress. Activities of glutathione peroxidase, glutathione reductase, and glutathione-S-transferase were also studied in liver, kidney, and gills. Levels of reduced glutathione (GSH) were measured in various tissues. Fish pretreated with cadmium and subsequently exposed to deltamethrin showed significantly reduced LPO values when compared with deltamethrin-exposed fish. Conversely, in the kidney, a potentiation response was observed. Deltamethrin exposure in fish resulted in significant alteration in activities of glutathione-dependent antioxidant enzymes. In the cadmium preexposed fish, which were subsequently exposed to deltamethrin, antioxidant enzymes showed a tendency toward normalization over deltamethrin-only exposed fish in liver and gills. GSH also showed a similar pattern in liver and gills but in kidney it remained elevated. Cadmium alone had no significant effect on various parameters at the concentration used in this study. When metallothionein (MT) induction was studied, only liver showed an MT-like protein band in sodium dodecylsulfate-polyacrylamide gel electrophoresis analysis. These results demonstrate a modulatory role of cadmium on the oxidative stress and other related parameters in liver and gills. These findings are important in the context of exposure to a mixture of pollutants in aquatic environment.

Topics: Animals; Cadmium; Gills; Glutathione; Glutathione Peroxidase; Glutathione Reductase; Glutathione Transferase; Insecticides; Kidney; Lipid Peroxidation; Liver; Metallothionein; Nitriles; Oxidative Stress; Perciformes; Pyrethrins; Thiobarbituric Acid Reactive Substances; Water Pollutants, Chemical