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[Oxidative stress of deltamethrin on rat nervous system]
Huang-yuan Li1, Nian Shi, Dan Chen
1Department of Health Toxicology, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province 430030, China.
Objective:
To explore the lipid peroxidation induced by deltamethrin (DM) in the cerebral cortex and hippocampus of rat.
Methods:
Wistar male rats were administrated with DM (daily dose was 3.125, 12.500 mg/kg respectively). The content of malondialdehyde (MDA) and the activity of total-superoxide dismutase (T-SOD, including Mn-SOD and CuZn-SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GSH-Px) and glutathione reductase (GR) in cerebral cortex and hippocampus tissue were determined. The reduced glutathione (GSH) content and gamma-glutamylcysteine synthetase (gamma-GCS) activity in cytosolic fraction of cerebral cortex and hippocampus tissue was determined by reversed-phase high performance liquid chromatographic assay with o-phthalaldehyde pre-column derivation.
Results:
(1) MDA content in cerebral cortex of the high dose group was significantly higher than those in the low dose group, and MDA content in hippocampus tissue of the high dose group was significantly higher than those in both the control and the low dose group after 5 d of DM exposure. (2) The activity of T-SOD and CuZn-SOD in cerebral cortex of both high and low dose group were significantly lower than that in the control group, and there was no effect on CAT activity in cerebral cortex (P < 0.01 or P < 0.05). (3) GSH content in cerebral cortex of the high dose group was significantly higher than that in control group (P < 0.05), and that in hippocampus tissue of high dose was significantly lower than that in both control and low dose group (P < 0.05). GR activity of low dose group in cerebral cortex was significantly lower than that in both control and high group [(11.80 +/- 5.15) vs (18.98 +/- 3.68), (17.35 +/- 2.47) U/mg pro] (P < 0.01). Gamma-GCS activity in hippocampus tissue of the high dose group was significantly lower than that in both control and low dose group [(1.75 +/- 0.60) vs (3.17 +/- 0.79), (2.72 +/- 0.75) nmol x mg pro(-1) x min(-1)] (P < 0.01). GR activity in hippocampus tissue of both high and low dose group was significantly lower than that in the control group [(21.63 +/- 4.92), (21.46 +/- 8.89) vs (31.22 +/- 6.97) U/mg pro] (P < 0.05).
Conclusion:
The oxidative stress in nerve tissue, which could be resulted from effect of DM on the activity of SOD, gamma-GCS and GR and GSH content, is one of the mechanisms of neuro-toxicity induced by DM; The decreased activity of gamma-GCS and GR may be the primary cause of DM-induced decrease in that GSH content in hippocampus tissue.
Insights
Deltamethrin (DM) exposure induces oxidative stress in rat brain tissues, evidenced by increased lipid peroxidation and altered antioxidant enzyme activities. Decreased gamma-glutamylcysteine synthetase and glutathione reductase activities may drive reduced glutathione levels in the hippocampus.
Area of Science:
- Neuroscience
- Toxicology
- Biochemistry
Context:
- Pesticide exposure and its neurological effects are a growing public health concern.
- Deltamethrin (DM) is a widely used pyrethroid insecticide with known neurotoxic potential.
- Understanding the specific mechanisms of DM neurotoxicity is crucial for risk assessment and mitigation.
Purpose:
- To investigate the impact of deltamethrin on lipid peroxidation and antioxidant defense systems in the rat cerebral cortex and hippocampus.
- To elucidate the biochemical pathways underlying deltamethrin-induced neurotoxicity.
Summary:
- Administration of deltamethrin to Wistar male rats at doses of 3.125 and 12.500 mg/kg/day for 5 days.
- Assessed malondialdehyde (MDA) levels, and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GSH-Px), glutathione reductase (GR), reduced glutathione (GSH), and gamma-glutamylcysteine synthetase (gamma-GCS).
- Deltamethrin exposure increased MDA content, decreased SOD and CuZn-SOD activities in the cerebral cortex, and altered GSH levels and gamma-GCS and GR activities in both brain regions, suggesting oxidative stress.
Impact:
- This study identifies oxidative stress as a key mechanism in deltamethrin neurotoxicity.
- The findings highlight the role of altered antioxidant enzyme activities, particularly gamma-GCS and GR, in deltamethrin-induced GSH depletion in the hippocampus.
- Results contribute to a better understanding of pesticide-induced neurological damage and inform safety guidelines.
