Allethrin induces oxidative stress, apoptosis and calcium release in rat testicular carcinoma cells (LC540)

The role of pyrethroid derivatives in autophagy and apoptosis crosstalk signaling and potential risk for malignancies

Pyrethroids and its derivatives widespread and uncontrolled continuous use has influenced multiple deleterious effects resulting in as a potential risk factor causing damage to the organ systems. Allethrin and prallethrin are extensively used yet their influences on human primary cells are very limited or under reported. The potential mechanisms by which allethrin and prallethrin modulates human primary cells, especially the molecular mechanisms or interconnectivity of autophagy-apoptosis, their clinical relevance in human subjects or patients are not well defined. In this current study, we've furnished the evidence that both allethrin and prallethrin user samples significantly induced Ccl2 mRNA expression, increased amount of reactive oxygen intermediate, inhibited membrane bound enzymes and altered membrane fluidity. Pyrethroid derivative users had induced levels of lipid peroxidation and induced binding activities of transcription factors(tfs) like CEBP-β and NF-AT. Pyrethroid derivatives induced autophagy, elicited intracellular Ca2+ concentration, calcineurin and regulated proapoptotic genes, DAPK1, Bim. Our current study presumably comprises the initial investigation of a very new mechanism of pyrethroid derivatives-moderated programed cell death in various cell sets or types, like human primary cells where-in this is a late event, is documented. Hence, current research-study might be significant in the various pyrethroid derivatives-allied hematological-related cancers and immunosuppressant or auto-immune disorders. In the foremost instance, we present data stating that pyrethroid derivatives induces multiple cell signaling cascades, like CEBP-β, NF-AT, ERK and MAPK having a role in autophagy thereby; synchronously effectively impact on the apoptosis, therefore causing hematological tumors and toxic or immune related disorders.

Interaction of the insecticide bioallethrin with human hemoglobin: biophysical, in silico and enzymatic studies

Bioallethrin is an insecticide that is widely used in households resulting in human exposure. Bioallethrin is cytotoxic to human erythrocytes. Here we have studied the interaction of bioallethrin with human hemoglobin (Hb) using in silico and biophysical approaches. Incubation of Hb (5 μM) with bioallethrin (1-50 µM) led to increase in absorbance at 280 nm while the Soret band at 406 nm was slightly reduced. The intrinsic fluorescence of Hb was enhanced with the appearance of a new peak around 305 nm. Synchronous fluorescence showed that the binding of bioallethrin to Hb mainly affects the tyrosine microenvironment. The structural changes in Hb were confirmed with a significant shift in CD spectra and about 25% loss of α-helix. Molecular docking and visualisation through Discovery studio confirmed the formation of Hb-bioallethrin complex with a binding energy of -7.3 kcal/mol. Molecular simulation showed the stability and energy dynamics of the binding reaction between bioallethrin and Hb. The structural changes induced by bioallethrin led to inhibition of the esterase activity of Hb. In conclusion, this study shows that bioallethrin forms a stable complex with human Hb which may lead to loss of Hb function in the body.Communicated by Ramaswamy H. Sarma.

Effect of a mixture of pyrethroids at doses similar to human exposure through food in the Indian context

Residual amounts of pyrethroids were detected in rice and vegetables of the Indian market. Thus, consumers are exposed to a mixture of pyrethroids on a daily basis through food. Though a large number of studies reported the toxic effects of pyrethroids, there are no reports that used doses equivalent to human consumption. In this study, male Wistar rats were exposed daily to a mixture of pyrethroids for 1-15 months which is equivalent to the amount present in rice and vegetables consumed by an average Indian each day. The oxidant-antioxidant status (lipid peroxidation, nitric oxide; activities of catalase, glutathione peroxidase, glutathione S transferase, and superoxide dismutase) and anatomical changes in the general organs (liver, lung, and kidney) and male reproductive tract tissues (caput, cauda, testis, and prostate) were evaluated. Further, liver and kidney function tests, lipid profile, and complete blood picture were analyzed. Increased oxidative stress, perturbations in the antioxidant enzyme activities, and damage to the anatomical architecture were observed. Disturbances in the liver function and lipid profile were significant. Results of our study demonstrate that exposure to a mixture of pyrethroids at a dose that is equivalent to human consumption can cause systemic and reproductive toxicity, which may ultimately result in the development of lifestyle diseases. This first line of evidence will fuel further studies to determine the impact of food-based pyrethroid exposure on the long-term health of humans and to envisage policies to reduce pesticide content in food products.

Allethrin Promotes Apoptosis and Autophagy Associated with the Oxidative Stress-Related PI3K/AKT/mTOR Signaling Pathway in Developing Rat Ovaries

The increased concern regarding the reduction in female fertility and the impressive numbers of women undergoing fertility treatment support the existence of environmental factors beyond inappropriate programming of developing ovaries. Among these factors are pyrethroids, which are currently some of the most commonly used pesticides worldwide. The present study was performed to investigate the developmental effects of the pyrethroid-based insecticide allethrin on ovarian function in rat offspring in adulthood. We mainly focused on the roles of oxidative stress, apoptosis, autophagy and the related pathways in ovarian injury. Thirty-day-old Wistar albino female rats were intragastrically administered 0 (control), 34.2 or 68.5 mg/kg body weight allethrin after breeding from Day 6 of pregnancy until delivery. We found that allethrin-induced ovarian histopathological damage was accompanied by elevations in oxidative stress and apoptosis. Interestingly, the number of autophagosomes in allethrin-treated ovaries was higher, and this increase was correlated with the upregulated expression of genes and proteins related to the autophagic marker LC-3. Furthermore, allethrin downregulated the expression of PI3K, AKT and mTOR in allethrin-treated ovaries compared with control ovaries. Taken together, the findings of this study suggest that exposure to the pyrethroid-based insecticide allethrin adversely affects both the follicle structure and function in rat offspring during adulthood. Specifically, allethrin can induce excessive oxidative stress and defective autophagy-related apoptosis, probably through inactivation of the PI3K/AKT/mTOR signaling pathway, and these effects may contribute to ovarian dysfunction and impaired fertility in female offspring.

Transgenerational effects on the fecundity and sperm proteome in rats exposed to a mixture of pyrethroids at doses similar to human consumption

Pyrethroid based pesticide usage for crop protection resulted in percolation of these compounds into the food chain. Toxicological studies that reflect exposure to pyrethroids through food in the human settings are rare. We conducted animal experimentations using a mixture of pyrethroids that is equivalent to the amount consumed by average individual through rice and vegetables in the Indian context. Male rats treated with a mixture of pyrethroids for 1-12 months displayed decreased transgenerational fecundity, sperm count, activities of 3β- and 17β-HSD and perturbed hormonal profile. At the transcriptome level, the expression of genes involved in spermatogenesis, steroidogenesis, germ cell epigenetic modulators and germ cell apoptosis were altered in the testis. In the sperm lysates of control rats, 506 proteins identified by mass spectrometry. The differential expression of these proteins (treated/control ratio) in the pyrethroid exposed rats was analyzed. Among the 506 proteins, 153 had a ratio of 0; 41 had a ratio ranging from >0 to <0.5; and 10 had a ratio >2.0. Interestingly, the differential expression was transgenerational. 26 proteins that were differentially expressed in the sperm of F0 treated rats continued to remain the same in the F1, F2 and F3 generations, while the differential expression was maintained up to F2 and F1 generations for 46 and 2 proteins respectively. Some of the proteins that continued to be differentially expressed in the later generations are reported to have critical roles in male reproduction. These results indicate that the reduced fecundity observed in the later generations could be due to the continued differential expression that was initiated by pyrethroid treatment in the F0 rats. Results of our study, for the first time, provide evidence that long-term exposure to pyrethroids affects transgenerational fecundity manifested by changes in sperm proteome.

In vitro toxicological assessment of flumethrin's effects on MCF-7 breast cancer cells

Pyrethroid pesticides are frequently used for household insect control of insects and in agriculture and livestock. Flumethrin is a pyrethroid that is used against ectoparasites in many animals. The goal of this study was to evaluate the cytotoxic, apoptotic, genotoxic, and estrogenic effects of flumethrin on the mammalian breast cancer cell line (MCF-7). Compared with control groups, a dose-dependent decrease was observed in cell viability at concentrations of 100 µM and higher. The cytotoxic and apoptotic effects detected by LDH assay and AO/EtBr staining increased significantly at a concentration of 1000 µM. The expression of BCL2, which is an anti-apoptotic gene, significantly decreased, whereas BAX, TP53, and P21 expression significantly increased. The results of a comet assay indicated that flumethrin significantly changed tail length, tail % DNA, tail moment, and Olive tail moment in concentrations above 1 and 10 µM. In addition, a 0.1 µM concentration of flumethrin affected ERα receptor mediated cell proliferation and increased transcription of estrogen-responsive pS2 (TFF1) and progesterone receptor (PGR) genes. As a result, flumethrin-induced apoptosis and cytotoxicity at a high concentration, while induced genotoxicity even at lower concentrations. Flumethrin is an endocrine disrupting insecticide with estrogenic effects at very low concentrations.

Pyrethroid based pesticides - chemical and biological aspects

Human and animal welfare primarily depends on the availability of food and surrounding environment. Over a century and half, the quest to identify agents that can enhance food production and protection from vector borne diseases resulted in the identification and use of a variety of pesticides, of which the pyrethroid based ones emerged as the best choice. Pesticides while improved the quality of life, on the other hand caused enormous health risks. Because of their percolation into drinking water and food chain and usage in domestic settings, humans unintentionally get exposed to the pesticides on a daily basis. The health hazards of almost all known pesticides at a variety of doses and exposure times are reported. This review provides a comprehensive summation on the historical, epidemiological, chemical and biological (physiological, biochemical and molecular) aspects of pyrethroid based insecticides. An overview of the available knowledge suggests that the synthetic pyrethroids vary in their chemical and toxic nature and pose health hazards that range from simple nausea to cancers. Despite large number of reports, studies that focused on identifying the health hazards using doses that are equivalent or relevant to human exposure are lacking. It is high time such studies are conducted to provide concrete evidence on the hazards of consuming pesticide contaminated food. Policy decisions to decrease the residual levels of pesticides in agricultural products and also to encourage organic farming is suggested.

Effect of oral administration of a mixture of pyrethroids at doses relevant to human exposure on the general and male reproductive physiology in the rat

Studies on the effects of unintentional intake of pyrethroid pesticides that are akin to actual human exposure settings are very rare. Such an exposure is primarily by consuming the food products as routine diet that contain residual levels of pyrethroids. In this study, rats were orally administered for 15 months with a mixture of pyrethroids at a dose that is one-fifth (high dose; HD) or one-twenty fifth (low dose; LD) of the residual levels commonly present in the average amount of rice and vegetables consumed by Indian population. Lipid profile, kidney and liver function were assessed. Lipid peroxidation, nitric oxide, antioxidant enzyme activities and histopathological changes were analyzed in the liver, lung, kidney, pancreas, testes, caput, cauda and prostate. The effect on the male reproductive system as a function of sperm count, enzyme activity of 3β-HSD and 17β-HSD and the expression profile of genes involved in spermatogenesis, steroidogenesis, genetic reprogramming and apoptosis of male gametes were evaluated. Significant increase in the relative organ weight, perturbations in the activities of antioxidant enzymes, lipid profile and liver function were observed in both LD and HD groups. Damage to the anatomical architecture was evident in all the tissues due to pyrethroid toxicity. Exposure to LD and HD of pyrethroid mixture resulted in decreased sperm count, activities of 3β-HSD and 17β-HSD, impaired capacitation and acrosome reaction and perturbations in the expression of genes that govern male gamete production. Results of our study indicate that exposure to pyrethroids for longer durations even at doses that are far below the residual levels present in the food consumed will result in severe damage to general physiological processes as well as reproductive function.

Bioallethrin-induced generation of reactive species and oxidative damage in isolated human erythrocytes

Bioallethrin is an insecticide that is widely used to control mosquitoes, fleas and cockroaches. The widespread use of bioallethrin has resulted in both occupational and non-occupational human exposure. Bioallethrin enters blood, regardless of the route of exposure, where it can interact with erythrocytes. We have studied the effect of bioallethrin on isolated human erythrocytes under in vitro conditions. Erythrocytes were incubated with increasing concentrations of bioallethrin (10-200 μM) for 4 h at 37 °C. Several biochemical parameters were analyzed in bioallethrin treated and untreated (control) cells. Incubation of erythrocytes with bioallethrin increased protein oxidation, lipid peroxidation and depleted sulfhydryl group content. Membrane damage was evident from cell lysis, osmotic fragility, inhibition of bound enzymes and transmembrane electron transport system. Bioallethrin also increased hemoglobin oxidation, heme degradation and the release of free iron moiety. This will decrease the oxygen transporting ability of blood. Bioallethrin treatment altered the specific activities of antioxidant enzymes and diminished the antioxidant power of cells. Scanning electron microscopy showed that bioallethrin treatment also altered erythrocyte mophology. Almost all changes were in a bioallethrin concentration dependent manner. The cytotoxicity of bioallethrin is probably mediated by reactive oxygen and nitrogen species whose formation was significantly enhanced in treated erythrocytes. Thus bioallethrin enhances the generation of reactive species which cause oxidative damage of cell components in human erythrocytes.

Antioxidant vitamin E protects embryos of Xenopus tropicalis against lambda-cyhalothrin induced embryotoxicity

Pesticides are capable of increasing risks to the early development of nontarget organisms through oxidative stress. The supplementation of antioxidants could help to modulate the toxic effects of pesticides, but much remains to be understood in the interactions between pesticides and antioxidants in amphibians. In the present study, the embryotoxicity of a widely used pyrethroid, lambda-cyhalothrin (LCT), and the potential effect of α-tocopherol (TOC) on embryos of Xenopus tropicalis were evaluated. Exposure to LCT did not affect the hatch rate, survival, or body length of the embryos. However, environmentally relevant concentrations of LCT could induce significant malformations on the larvae. Exposure to LCT led to a concentration-dependent induction of oxidative stress and cytotoxicity that subsequently resulted in embryotoxicity. During the early developmental stages, vitamin E could work as a powerful protective antioxidant. The LCT-induced overproduction of reactive oxygen species and increased enzymatic activities were fully inhibited by treatment with 1 μg/L TOC. However, only supplementation with 100 μg/L TOC provided partial protection against the morphological changes caused by LCT. The results from the present study suggest that antioxidant vitamin E possesses protective potential against pyrethroid-induced embryotoxicity in amphibian embryos through the prevention of oxidative stress.

Effects of pyrethroid insecticides on hypothalamic-pituitary-gonadal axis: A reproductive health perspective

Pyrethroids, a class of ubiquitous insecticides, have been recognized as endocrine-disrupting chemicals (EDCs). A lot of studies have implied the endocrine-disrupting effects of pyrethroids on the hypothalamic-pituitary-gonadal (HPG) axis. However, there are few review articles regarding the effects of pyrethroids on the HPG axis of mammal and human, especially new research progress made in this area. The present review sums up the effects of pyrethroids on the HPG axis-related reproductive outcomes, including epidemiological investigations based on human biomonitoring, animal studies and in vitro tests. Mechanisms have described that the endocrine-disrupting effects of pyrethroids on mammal can be mediated via the interaction with steroid receptors, the direct action on ion channels and signaling molecules. Finally, we summarize the current research gaps and suggest future directions in this topic.

Modulation of Diabetes Mellitus-Induced Male Rat Reproductive Dysfunction with Micro-Nanoencapsulated Echinacea purpurea Ethanol Extract

Diabetes mellitus is a major health problem that affects a patient's life quality throughout the world due to its worst complications. It was recognized that chronic hyperglycemia with oxidative stress was the major cause of male infertility. Echinacea purpurea ethanol extract (EE) contains phenolic acid and isobutylamides had been proven to ameliorate diabetic complications. Chitosan/silica nanoparticles are well-known in the medicinal field because of its controlled release and drug delivery properties. This study was aimed at investigating whether the EE encapsulated chitosan/silica nanoparticle (nano-EE) can enhance the amelioration of male infertility. Our results indicated that the average size of nano-EE was 218 ± 42 nm with an encapsulation efficiency of 66.9% and loading capacity of 39.9%. The reduction in oxidative stress and antioxidant activity of nano-EE was observed in LC-540 cells. In in vivo experiment, 33 mg/kg of streptozotocin (STZ) was used to induce diabetes in male Sprague-Dawley rats. Diabetic rats were treated with nano (465 mg/kg), nano-EE 1 (93mg/kg), nano-EE3 (279mg/kg), nano-EE5 (465 mg/kg), and metformin (Met) (200 mg/kg) for 7 weeks. The results show that the nano-EE5 can improve hyperglycemia, insulin resistance, and plasma fibroblast growth factor 21 (FGF 21) resistance. It was also confirmed that nano-EE5 significantly improved the testis tissue structure, increasing sperm quality and DNA integrity as well as reducing reactive oxygen species level.

Allethrin toxicity causes reproductive dysfunction in male rats

Pyrethroids are widely used for domestic and agricultural purposes and their use is increasing, especially in developing countries. Uncontrolled use of these insecticides resulted in their entry into the food chain thereby causing toxicity to different organ systems. Allethrin is one of the widely used pyrethroids, but its toxicological effects are underreported when compared to other pyrethroids. Further, its effects on the male reproductive tract remain uncharacterized. In this study, its toxicity on the male reproductive tract was evaluated by administering 25-150 mg/kg body weight allethrin to adult rats for 60 days. The mRNA expression of factors that are important in spermatogenesis (Scf, c-Kit, Hsf2, Ovol1, Brdt, Kdm3A, Ybx-2, and Grth) and steroidogenesis (StAR, 3β-HSD, 17β-HSD) was significantly downregulated. Decreased levels of testosterone, reduced sperm count and daily sperm production was also observed due to allethrin toxicity. However, sperm quality parameters assessed by computer-assisted sperm analyzer were not affected. Spermatozoa obtained from allethrin-treated rats failed to undergo acrosome reaction. Results of this study indicate that allethrin affects spermatogenesis and sperm function, thus lending further support to the growing evidence of its toxicity.

Effect of epigallocatechin-3-gallate on acrylamide-induced oxidative stress and apoptosis in PC12 cells

Acrylamide (ACR) is a chemical intermediate utilized in industry. ACR is also formed during heating of foods containing carbohydrates and amino acids. Therefore, humans are widely exposed to ACR, and ACR neurotoxicity in humans is a significant public health issue attracting wide attention. In this study, we investigated the potential neuroprotective effects of epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic compound in green tea, in PC12 cells treated with ACR. ACR-treated PC12 cells pretreated with various concentrations of EGCG (2.5, 5 and 10 μM) for 24 h had increased viability and acetylcholinesterase activity and reduced apoptosis and necrosis compared to cells exposed to ACR alone. EGCG reduced the expression of bax mRNA, decreased cytochrome c release, reduced intracellular calcium levels, inactivated caspase 3 and increased mitochondrial membrane potential, suggesting that EGCG prevents ACR-induced apoptosis through a mitochondrial-mediated pathway. In addition, EGCG inhibited the formation of reactive oxygen species and lipid peroxidation while enhancing superoxide dismutase activity and glutathione levels, thereby reducing oxidative stress. Our results indicate that pretreatment of PC12 cells with EGCG attenuates ACR-induced apoptosis by reducing oxidative stress. Therefore, drinking green tea may reduce nerve injury induced by ACR.

Cis-bifenthrin causes immunotoxicity in murine macrophages

Synthetic pyrethroids (SPs) are commonly used insecticides that have been detected in mammals, including humans, indicating a potential threat to human health. Bifenthrin (BF), as well as other pyrethroids, has been shown to possess neurotoxic, reproductive, hepatotoxic and nephrotoxic potential in mammals. However, studies regarding the immunotoxicity of BF and its mechanism are limited. In this study, we aim to exam the immunotoxicity of cis-BF on the murine macrophage cell line, RAW 264.7. MTT assay results demonstrated that cis-BF exposure induced apoptosis in RAW 264.7 cells in a concentration-dependent manner. We found that the expression of p53 and caspase-3 was up-regulated, while the expression of Bcl-2 was down-regulated during cis-BF-induced apoptosis. In addition, we also found that cis-BF exposure caused oxidative stress in RAW 264.7 cells in a dose-dependent manner. Interestingly, cis-BF exposure was found to inhibit the increase in transcription levels of IL-1β, IL-6 and TNF-α responding to LPS stimulation. We also found that the induced increase in IFN-β mRNA levels upon Sendai virus infection was blocked with cis-BF exposure. Finally, we found that cis-BF exposure increased ROS levels and dysregulated mRNA levels of oxidative stress-related genes in RAW 264.7 cells. The present study elucidates the immunotoxicity effect of cis-BF on macrophages and its possible underlying mechanism. The results from this study support the necessity to evaluate immune dysfunction in the risk assessment of cis-BF exposure.

Urolithin C, a gut metabolite of ellagic acid, induces apoptosis in PC12 cells through a mitochondria-mediated pathway

Urolithin C includes apoptosis in PC12 cells through a mitochondria-mediated pathway.