Purine bases oxidation and repair following permethrin insecticide treatment in rat heart cells

Pollutants including insecticides have been recently reported to be a risk factor involved in various diseases. Permethrin, a member of the family of synthetic pyrethroids, is widely used as insecticide in agriculture and other domestic applications. To investigate possible cardiotoxicity, we had examined different concentrations of permethrin on the freshly isolated rat heart cells using the alkaline comet assay. A significant difference in % tail DNA between all concentrations of permethrin (5, 10, 20 μM) and vehicle (control) without enzymes and with Fpg-treated cells were measured. The results indicated that permethrin induced oxidative damage to purine bases in the heart cells. Pyrimidines oxidation was evaluated using Endonuclease III (Endo III), but the results did not reveal any significant changes. After permethrin exposure, cells were studied to evaluate their DNA repair capacity. A complete DNA repair at 10 and 20 μM was measured after 30 and 60 min of repair intervals. Significant change in plasma membrane fluidity at different depths of bilayer was measured following permethrin treatment. Membrane fluidity in the hydrophilic–hydrophobic region was reduced, while the hydrophobic inner resulted more fluid following permethrin treatment of heart cells. This work points to standardize conditions applicable to ex vivo cells following in vivo treatment in order to study the cardiotoxicity of insecticide

Early life permethrin treatment leads to long-term cardiotoxicity.

Environmental, nutritional or hormonal influences in early life may have long-term effects changing homeostatic processes and physiological parameters in adulthood. NF-kB and Nrf2, two of the main transcription factors regulating genes involved in pro-inflammatory and antioxidant responses respectively, can be modified by various stimuli. NF-kB controls immediate early genes and is required for cardiomyocyte hypertrophic growth, while Nrf2 protects the heart from oxidative stress-induced cardiovascular complications. The aim of this study was to investigate the impact of early life permethrin treatment (1/50 of LD50, from 6th to 21st day of life) on the development of cardiotoxicity in 500-day-old rats. Nrf2 and NF-kB gene expression, calcium level and heart surface area were chosen as biomarkers of toxicity. Six candidate reference genes were first examined and GAPDH resulted the most stable one for RT-qPCR. The comparative expression analysis of the target genes showed 1.62-fold increase in Nrf2 mRNA level, while the NF-kB mRNA in treated rats was not significantly changed compared to control ones. A significant decrease in heart surface area was observed in treated rats (296.59±8.09, mm2) with respect to the control group (320.86±4.93, mm2). Finally, the intracellular calcium influx in heart of early life treated rats increased 4.33-fold compared to the control one. In conclusion, early life pesticide exposure to low doses of permethrin insecticide, has long-term consequences leading to cardiac hypotrophy, increased calcium and Nrf2 gene expression levels in old age

Early life permethrin exposure induces long-term brain changes in Nurr1, NF-kB and Nrf-2

Pesticide exposure during brain development represents an important risk factor for the onset of brain-aging processes. Here, the impact of permethrin administered to rats from 6th to 21st day of life, at a dose near to "no observed adverse effect level" (NOAEL), was studied when animals reached 500 day-old. The permethrin treatment induced a decrease in Nurr1 gene expression in striatum, an increase in hippocampus and cerebellum, while the protein level changed only in striatum where it was increased. NF-kB p65 gene expression was increased in cerebellum, while its protein level augmented in cerebellum and in prefrontal cortex and decreased in hippocampus of treated rats compared to control ones. Nrf-2 gene expression resulted significantly higher only in cerebellum of treated animals. The results suggest that early life permethrin treatment induces long-lasting effects leading to dopaminergic neuronal disorders, monitored by Nurr1 alteration. Moreover the impairment of NF-kB and Nrf-2, important for the balance between pro- and anti-inflammatory systems, confirms that the neonatal permethrin treatment can influence genes involved with the onset of brain-ageing processes

Prolonged swimming promotes cellular oxidative stress and p66Shc phosphorylation, but does not induce oxidative stress in mitochondria in the rat heart

Abstract Exercise-induced changes in p66Shc-dependent signaling pathway are still not fully understood. The p66Shc protein is one of the key players in cell signaling, particularly in response to oxidative stress. Therefore, the aim of this study was to investigate the effect of prolonged swimming on the phosphorylation of p66Shc as well as the induction of mitochondrial and cellular oxidative stress in rat hearts. Male Wistar rats were divided into a sedentary control group and an exercise group. The exercised rats swam for 3 hours and were burdened with an additional 3% of their body weight. After the cessation of exercise, their hearts were removed immediately for experiments. The exercise protocol caused increased levels of the following oxidative stress parameters in cardiac cells: DNA damage, protein carbonyls, and lipid dienes. There was also increased phosphorylation of p66Shc without any alterations in Akt and extracellular signal-regulated kinases. Changes in the ferritin L levels and the L to H subunit ratio were also observed in the exercised hearts compared with the control hearts. Despite increased phosphorylation of p66Shc, no significant increase was observed in either mitochondrial H2O2 release or mitochondrial oxidative stress markers. Regardless of the changes in phosphorylation of p66Shc, the antioxidant enzyme activities (superoxide dismutase and catalase) and anti-apoptotic (Bcl2), and pro-apoptotic (Bax) protein levels were not affected by prolonged swimming. Further studies are required to investigate whether p66Shc phosphorylation is beneficial or detrimental to cardiac cells after exercise cessation

The genoprotective activity of resveratrol on permethrin-induced genotoxic damage in cultured human lymphocytes

The aim of this work was to investigate the genetic effects of resveratrol (RSV) at concentrations of 10, 15, 25, 40, 75 and 100 µM and its activities on the genotoxicity induced by the permethrin (PM) (200 µM). After the application of PM and RSV, separately and together, cultured human lymphocytes were assessed by chromosome aberrations (CA) and sister chromatid exchange (SCE) tests. According to results, the frequencies of CA and SCE rates in the peripheral lymphocytes were significantly increased by PM compared with the controls. However, RSV had no genotoxic effect. Furthermore, the findings revealed that PM-induced increases in the mean frequencies of both genotoxic indices were diminished by RSV in a clear dose dependent manner, indicating its protective role towards the cells from PM exerted injury. In conclusion, these effects of RSV should be considered while evaluating the possible use of RSV as a therapeutic agent