Chlorpyrifos Induced Region Specific Vulnerability in Rat CNS and Modulation by Age and Cold Stress: An Interactive Study

Chlorpyrifos (CPF)​, an organophosphorus insecticide is known to cause ill health in non-​target animals by inducing oxidative stress. In this study influence of cold stress (15°C and 20°C) and age as modulating factors on CPF induced oxidative stress was addressed to assess age-​related differences and vulnerability in central nervous system of rats. The results indicated an interaction with age and cold exposure resulting in marked decreased activity levels of SOD (P < 0.05)​, CAT (P < 0.05)​, GPx (P < 0.05)​, GST (P < 0.05) followed by increased MDA (P < 0.05) and decreased GSH levels (P < 0.05)​. The ANOVA and Post-​hoc anal. showed that antioxidant enzymes decreased significantly (P < 0.05) on CPF exposure. Moreover synergistic action of CPF and cold stress at 15°C caused higher inhibition on comparison with CPF and cold stress alone and together at 20°C indicating the extent of peroxidative damage in discrete regions of CNS. Further this study showed young individuals to be more sensitive than adults

Mitochondrial Dysfunction in Aging Rat Brain Regions upon Chlorpyrifos Toxicity and Cold Stress: An Interactive Study

Mitochondrial dysfunction and consequent energy depletion are the major causes of oxidative stress resulting to bring alterations in the ionic homeostasis causing loss of cellular integrity. Our previous studies have shown the age-associated interactive effects in rat central nervous system (CNS) upon co-exposure to chlorpyrifos (CPF) and cold stress leading to macromolecular oxidative damage. The present study elucidates a possible mechanism by which CPF and cold stress interaction cause(s) mitochondrial dysfunction in an age-related manner. In this study, the activity levels of Krebs cycle enzymes and electron transport chain (ETC) protein complexes were assessed in the isolated fraction of mitochondria. CPF and cold stress (15 and 20 °C) exposure either individually or in combination decreased the activity level of Krebs cycle enzymes and ETC protein complexes in discrete regions of rat CNS. The findings confirm that cold stress produces significant synergistic effect in CPF intoxicated aging rats. The synergism between CPF and cold stress at 15 °C caused a higher depletion of respiratory enzymes in comparison with CPF and cold stress alone and together at 20 °C indicating the extent of deleterious functional alterations in discrete regions of brain and spinal cord (SC) which may result in neurodegeneration and loss in neuronal metabolic control. Hence, co-exposure of CPF and cold stress is more dangerous than exposure of either alone. Among the discrete regions studied, the cerebellum and medulla oblongata appears to be the most susceptible regions when compared to cortex and SC. Furthermore, the study reveals a gradual decrease in sensitivity to CPF toxicity as the rat matures

Cold stress interaction on organophosphate insecticide poisoning: Age-related assessment in rat cerebral cortex

110-116The present study was undertaken to identify the nature of the interactive effects of chlorpyrifos (CPF) and cold stress (15° and 20°C) on the activities of acetyl cholinesterase (AChE), choline acetyl transferase (ChAT), Na+, K+-ATPase and malondialdehyde (MDA) level in the cerebral cortex of 1 week, 3 weeks and 3 months of age. The results indicated an interaction of CPF with age of animal and cold exposure resulting in marked decrease in the activity levels of AChE, ChAT, Na+, K+-ATPase, followed by increased MDA levels. Overall, the effects of co-exposure of cold stress and CPF were appreciably different from either of the exposures. However, synergistic-action of CPF and cold stress at 15°C showed a greater inhibition of AChE, ChAT, and Na+, K+-ATPase in comparison with CPF or cold stress alone and together at 20°C. The results reveal that young animals are markedly more sensitive to interactive effects of CPF and cold stress than adults