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Neurodevelopmental consequences of gestational exposure (GD14-GD20) to low dose deltamethrin in rats
M H Aziz1, A K Agrawal, V M Adhami
1Developmental Toxicology Division, Industrial Toxicology Research Center, Mahatma Gandhi Marg, Post Box no. 80, 1 U.P., Lucknow, India.
Insights
Low-level prenatal exposure to deltamethrin (DT) in rats impairs brain development, affecting neurobehavioral and neurochemical functions. These adverse effects on the developing brain persist into adulthood, indicating long-term neurotoxicity.
Area of Science:
- Neuroscience
- Toxicology
- Developmental Biology
Background:
- Prenatal exposure to environmental toxins can impact neurodevelopment.
- Deltamethrin (DT) is a widely used pyrethroid insecticide.
- Understanding the long-term neurodevelopmental effects of low-level DT exposure is crucial.
Purpose of the Study:
- To investigate the neurobehavioral, neurochemical, and immunohistochemical effects of low-level in utero deltamethrin (DT) exposure.
- To assess the persistence of these effects in postnatal rats at 6 and 12 weeks.
Main Methods:
- Gestational exposure of rats to deltamethrin (DT) (1mg/kg) from day 14-20 of gestation.
- Assessment of neurobehavioral (learning and memory), neurochemical (acetylcholinesterase activity, muscarinic receptor binding), and immunohistochemical (Growth Associated Protein-43) parameters.
- Postnatal evaluation at 6 and 12 weeks.
Main Results:
- DT exposure led to increased acetylcholinesterase activity and decreased muscarinic receptor binding in the hippocampus.
- Significant deficits in learning and memory performances were observed in DT-exposed rats.
- Aberrant increase in Growth Associated Protein-43 expression was noted in the hippocampus, suggesting altered neuronal differentiation and synaptogenesis.
Conclusions:
- Low-level in utero deltamethrin (DT) exposure adversely affects developing rat brains during critical growth periods.
- Neurobehavioral and neurochemical impairments persist up to 12 weeks postnatally with no significant recovery.
- DT exposure during gestation poses a risk for long-term neurodevelopmental deficits.
Abstract:
Effect of low level in utero exposure to deltamethrin (DT) (1mg /kg wt.) during gestation day 14-20 was studied on selected neurobehavioral, neurochemical, immunohistochemical parameters in rats at 6 and 12 weeks postnatal period. The significant increase in acetylcholinesterase activity and decrease in (3)H-quinuclidinyl benzilate binding in the hippocampal region of DT exposed animals, suggesting impairment in cholinergic (muscarinic) receptors. A significant decrease in the learning and memory performances was also observed both at 6 and 12 weeks, which is directly correlated with decrease in muscarinic receptor binding. Immunohistochemistry and image analysis of growth associated protein-43, a neuron specific protein present in axonal growth cone and a marker for neuronal differentiation and synaptogenesis, exhibit aberrant increase in its expression in the hippocampus in DT exposed rats at both time periods. The data suggests that low level exposure to DT in utero during brain growth spurt period adversely affects the developing brain and the changes persist even up to 12 weeks postnatal period in rats. Although there is no significant recovery at 12 weeks assessment but still significant impairment persist on biochemical and behavioural parameters.