Effects of cypermethrin, propetamphos, and combination involving cypermethrin and propetamphos on lipid peroxidation in mice

Protective role of olive oil extract of propolis on short and long-term administration of tamoxifen in rats

Tamoxifen (TAM) is an antiestrogenic agent used for adjuvant treatment in estrogen receptor-positive breast cancers in the pre/post-menopausal period. This study, it was aimed to determine the effect of olive oil extract of propolis (OEP) on short and long-term administration of TAM in rats. Wistar albino rats were divided into groups with eight animals in each. Groups: control, OEP, TAM, and OEP + TAM. At the end of the experiment, oxidative stress tests were performed with Enzyme-Linked ImmunoSorbent Assay (ELISA) on blood and tissue samples (liver, kidney, and ovary) taken from rats. After single-dose TAM administration, there was a significant increase in red blood cell, hematocrit, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration levels compared to the control group, a decrease in low-density lipoprotein (LDL) value, a significant increase in liver enzymes and fasting glucose values was detected compared with the control and propolis groups. A normalizing effect was observed in the group given OEP and TAM combined. The increase in Malondialdehyde (MDA) and the decrease in enzyme activities in tissues are also noteworthy. Propolis application reduced the tissue damage caused by TAM. In addition, improved cytokine levels, which increased with TAM administration. It has been concluded that OEP can be given in supportive treatment, as it improves hematological and antioxidant parameters in TAM treatment.

Pesticides compromise health: a comparison between lizards collected within and outside an agricultural area

Reptiles are the least studied vertebrates regarding the impact of pesticides on their health, despite being good models for ecotoxicological studies given their abundance and easy handling. Salvator merianae is widely distributed in South America and often found in agricultural cultivation areas. Here, we compared the morphological, biochemical, and physiological parameters of S. merianae from an exposed area (EA) to pesticides and a reference area (RA) or control. These parameters were measured in plasma (albumin, alanine transaminase, alkaline phosphatase, gamma-glutamyl transpeptidase, glucose, total proteins, uric acid, triglycerides, VLDL, and corticosterone) and in erythrocytes (TBARS, glutathione S-transferase, superoxide dismutase, and catalase activity). Blood samples were collected from 28 lizards (EA: three juveniles, three adult females, and three adult males; RA: nine juveniles, four females, and five males) in southern Brazil during the reproductive period. We observed a decrease in body mass, the ratio between body mass and total length and snout-vent length in juvenile lizards collected at EA. The levels of TBARS, glutathione S-transferase, triglycerides, VLDL, and uric acid were altered for juveniles in EA. When comparing the two areas, females differed in superoxide dismutase activity and total proteins, while males differed in superoxide dismutase, catalase, and glutathione S-transferase activity. This set of results shows that S. merianae, especially juveniles, suffers a negative impact when inserted in an agricultural area. The analyzed biomarkers proved suitable for monitoring these lizards and the quality of this environment.

Selenium alleviates biological toxicity of thiamethoxam (TMX): Bioaccumulation of TMX, organ damage, and antioxidant response of red swamp crayfish (Procambarus clarkii)

Pesticides are important for agricultural development; however, animals involved in rice-fish farming absorb the pesticides used during the farming process. Thiamethoxam (TMX) is extensively used in agriculture and is gradually occupying the market for traditional pesticides. Therefore, this study aimed to investigate whether selenomethionine (SeMet) could affect the survival rate, bioaccumulation of TMX, serum biochemical parameters, lipid peroxidation, antioxidants in the hepatopancreas, and expression of stress genes after exposure of red swamp crayfish to 10 ppt TMX for 7 days. The results showed that the survival rate significantly increased and the bioaccumulation of TMX significantly decreased with SeMet administration (P < 0.05). Furthermore, severe histological damage to the hepatopancreas of red crayfish was observed after exposure to TMX; however, this damage was alleviated after SeMet administration. SeMet also significantly reduced the TMX-induced changes in serum biochemical parameters, malondialdehyde content, and antioxidant enzyme activity in crayfish hepatopancreas (P < 0.05). Notably, analysis of the expression of 10 stress response genes showed that 0.5 mg/kg SeMet might decrease cell damage in the hepatopancreas. Consequently, our findings suggest that higher levels of TMX in crayfish may cause hepatopancreatic cell toxicity, which can be harmful to human health; however, SeMet could mitigate these effects, providing an understanding of pesticide compounds and food safety.

Immunomodulatory effect of imidacloprid on macrophage RAW 264.7 cells

The neonicotinoid imidacloprid was promoted in the market because of widespread resistance to other insecticides, plus its low mammalian impact and higher specific toxicity towards insects. This study aimed to evaluate the immunomodulatory effect of imidacloprid on macrophages. RAW 264.7 cells were incubated to 0-4000mg/L of imidacloprid for 24 and 96h. Imidacloprid presented a concentration-dependent cytotoxicity after 24h and 96h incubation for MTT reduction (3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide) (EC₅₀ 519.6 and 324.6mg/L, respectively) and Neutral Red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) assays (EC₅₀ 1139.0 and 324.2mg/L, respectively). Moreover, imidacloprid decreased the cells' inflammatory response and promoted a mitochondrial depolarization. The complex II and succinate dehydrogenase (SDH) activities in RAW 264.7 cells incubated with imidacloprid increased more at 24h. These results suggest that imidacloprid exerts an immunomodulatory effect and mitochondria can act as regulator of innate immune responses in the cytotoxicity mediated by the insecticide in RAW 264.7 cells.

AccsHSP21.7 enhances the antioxidant capacity of Apis cerana cerana

BACKGROUND

The widespread use of glyphosate has many adverse effects on Apis cerana cerana. Due to the incomplete understanding of the molecular mechanisms of glyphosate toxicity, there are no available methods for mitigating the threat of glyphosate to Apis cerana cerana. Small heat shock proteins (sHSPs) play an important role in resisting oxidative stress, but their mechanism of action in Apis cerana cerana remains unclear.

RESULTS

In this experiment, we cloned and identified AccsHSP21.7. Studies have shown that AccsHSP21.7 contains binding motifs for various transcription factors related to oxidative stress. Abiotic stresses induced the expression of AccsHSP21.7. Bacteriostatic testing of a recombinant AccsHSP21.7 protein proved that Escherichia coli overexpressing AccsHSP21.7 showed increased resistance to oxidative stress. Knocking down the AccsHSP21.7 gene caused significant damage to midgut cells, which seriously disrupted the antioxidant system in Apis cerana cerana and greatly increased mortality under glyphosate stress.

CONCLUSION

This study investigated the relationship between antioxidant regulation and the AccsHSP21.7 gene at the molecular level, and the results have guiding significance for the improvement of stress resistance in Apis cerana cerana. © 2023 Society of Chemical Industry.

The protective effect of chrysin against oxidative stress and organ toxicity in rats exposed to propetamphos

The aim of this study was to investigate the protective efficacy of chrysin against propetamphos exposure. For this purpose, 2 to 3-month-old 40 male Wistar Albino rats were used. These animals were randomly assigned to four groups. The animals in the control group received the vehicle substance (corn oil) alone. Groups 2, 3 and 4 were administered with 50 mg/kg.bw/day of chrysin (in corn oil), 10 mg/kg.bw/day of propetamphos (in corn oil), and 10 mg/kg.bw/day of propetamphos plus 50 mg/kg.bw/day of chrysin, respectively, for 28 days. Some oxidative stress/lipid peroxidation parameters (MDA, SOD, CAT, GSH-Px, NO, glutathione) and serum biochemical parameters (triglyceride, cholesterol, creatinine, BUN, creatine phosphokinase, ALT, ALP and pseudocholinesterase) were analyzed in tissue/blood samples. Also, histopathological findings were observed. According to the data obtained, no significant alteration had occurred in these parameters and the histological findings in the group given chrysin alone, when compared to the control group. Significant unfavorable alterations were detected in the oxidative stress/lipid peroxidation/antioxidant status parameters, all biochemical parameters and histopathological findings of the group that received propetamphos alone. In the group that was given both chrysin and propetamphos, remedial/recovery alterations were observed in the oxidative stress/lipid peroxidation/antioxidant status values, serum biochemical parameters and histopathological findings, such that the values and histopathological findings showed partly similarity to those of the control group. In result, it is suggested that chrysin may provide protection against propetamphos exposure and propetamphos-induced organ damage in rats at a certain level.

Melatonin enhances the antioxidant capacity to rescue the honey bee Apis mellifera from the ecotoxicological effects caused by environmental imidacloprid

Imidacloprid severely poisons the nontarget insect honey bee Apis mellifera. Few treatments are available to mitigate the adverse effects of imidacloprid. The primary concern is that the molecular understanding of imidacloprid toxicity is not comprehensive enough. Oxidative stress is the primary pathophysiological mechanism by which pesticides cause high mortality. Our pilot study found for the first time that imidacloprid stimulates bee brains to secrete melatonin, a free radical scavenger. However, the molecular basis for imidacloprid toxicity and the role of melatonin in coping with imidacloprid have not been systematically investigated in bees. This study administered an environmental dose of imidacloprid (36 ng/bee) orally to A. mellifera. The detoxification gene cytochrome P450 CYP4G11 was significantly induced. However, potent cytotoxicity of imidacloprid suppressed the expression of the antioxidants catalase (CAT) and thioredoxin reductase (TrxR), and the activity of guaiacol peroxidase (GPX), superoxide dismutase (SOD), and reduced glutathione (GSH) was not induced. The levels of reactive oxygen species (ROS) and the lipid peroxidation marker malondialdehyde (MDA) were increased. The expression of the apoptotic genes cysteinyl aspartate specific proteinase (Caspase-3) and apoptosis inducing factor (AIF) increased, and the apoptotic features of midgut cells were prominently apparent. These results suggest that imidacloprid disrupts the bee antioxidant system, causing severe oxidative stress and tissue damage and ultimately leading to apoptosis. Significantly, however, imidacloprid exposure also stimulated bee brains to continuously secrete melatonin. Further preadministration of exogenous melatonin (200 ng/bee) orally to bees significantly reversed and enhanced the activity of the imidacloprid-suppressed antioxidants CAT, SOD, and GSH, which allowed imidacloprid-induced ROS accumulation to be effectively alleviated. The MDA content, apoptotic genes Caspase-3 and AIF, and detoxification gene CYPG411 expression were restored to normalization; midgut cell damage, apoptosis, and mortality were significantly reduced. These findings strongly suggest that melatonin enhanced bee antioxidant capacity, thus attenuating oxidative stress and apoptosis to confer imidacloprid tolerance to honey bees. Melatonin secretion may be a defense mechanism to mitigate imidacloprid toxicity.

Toxicological effects of acute prothioconazole and prothioconazole-desthio administration on liver in male Chinese lizards (Eremias argus)

Prothioconazole (PTC) is a high effective systemic fungicide, and one of its major metabolites is prothioconazole-desthio (PTC-d). Because of its wildly use in the farmland of China, the local eco-toxicological effects of PTC as well as PTC-d are needed to be concerned. This study investigated hepatoxicity of Chinese lizards (Eremias argus), a local non-target organism, after single dose oral treated (100 mg kg^-1 BW) through pathological, enzyme activity and gene expression analysis. PTC treatment caused ballooning and PTC-d treatment led to macrovesicular steatosis of hepatocyte. The elevation of serum indexes, including the activities of aspartate aminotransferase (AST), alkaline phosphatase (ALP) and alanine aminotransferase (ALT), further confirmed the hepatic injury. PTC and PTC-d treatments altered oxidative status reflected by the inhibition of superoxide dismutase (SOD) activity , meanwhile, the stimulation of catalase (CAT) activity, glutathione peroxidase (GPx) activity and malondialdehyde (MDA) content. The mRNA expression changes of apoptosis-related factors and cytokines genes, including Bax, Bcl-2, TNF-α, NF-κB, Caspase-3 and Nrf2, deeply uncovered the potential mechanism of hepatotoxicity caused by PTC and PTC-d. In brief, the results indicated that both of these two compounds altered oxidative status, then were likely to trigger caspase-3 by affecting the ratio of pro- and anti-apoptotic factors which belong to intrinsic apoptosis pathway. Specifically, more serious impacts were induced by PTC-d than its parent compound. This study is the first to provide specific insight into potential hepatotoxicity resulted from PTC and PTC-d in male Chinese lizards.

Thiamethoxam-mediated alteration in multi-biomarkers of a model organism, Galleria mellonella L. (Lepidoptera: Pyralidae)

Thiamethoxam (TMX), a second-generation neonicotinoid, is extensively used to control numerous pests that infest crops. We investigated the effects of TMX (10, 20, 30, 40, and 50 μg/mL for 24, 48, 72, and 96 h) on biomarkers such as antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)); malondialdehyde (MDA), protein, lipid, and carbohydrate levels; micronucleus formation; and total hemocyte count in a model organism, Galleria mellonella L. SOD and CAT activities significantly decreased after 72 and 96 h of treatment at all TMX concentrations compared with control. MDA level increased following treatment with all TMX doses, with the exception of that following treatment with the lowest dose (10 μg/mL) at all tested treatment durations. Lipid and carbohydrate levels significantly decreased following treatment with high doses of TMX (40 and 50 μg/mL) after 48, 72, and 96 h. Micronucleated cell number significantly increased following treatment with all TMX doses at all tested treatment durations, except with 10 μg/mL of TMX for 24 h, when compared with control. During the first 72 h, total hemocyte count significantly decreased following treatment with 20-, 30-, 40-, and 50-μg/mL TMX; however, it was significantly reduced at all doses of TMX after 96 h. These results suggest that TMX can induce immunotoxicity, oxidative stress, and genotoxicity in a potential target and also in the model organism, G. mellonella. In addition, our study provides additional information regarding the prospective toxic effects of TMX.

Pendimethalin-induced oxidative stress, DNA damage and activation of anti-inflammatory and apoptotic markers in male rats

Male Wistar rats were exposed to herbicide, pendimethalin (PND) at varying oral doses of 62.5, 125 and 250 mg/kg b.w. for 14 days. Toxiological effects were assessed in terms of oxidative stress, DNA damage, histopathological alterations and induction of anti-inflammatory and apoptotic responses linked Bax, Bcl-2, IFN-γ, TNF-α and caspase-3 gene expression. In comparison with respective untreated controls, all exposure groups of PND exhibited significant changes in the oxidative stress markers (protein carbonylation and lipid peroxidation) and antioxidant defenses (GSH, SOD, CAT and GST) in liver and kidney tissues. The histopathological changes including leucocyte infiltration, pyknotic nuclei, necrosis, large bowman’s space, shrinked renal cortex, were observed in the liver and kidney tissues of PND exposed rats. Significant DNA damage was recorded through comet assay in liver and kidney cells of treated animals as compared to control. Alteration in anti-inflammatory and apoptotic genes expression determined by RT-PCR, revealed the activation of intrinsic apoptotic pathway(s) under the PND induced cellular stress. A pronounced increase in Bax expression, caspase-3 activities and decreased Bcl-2 expressions were also associated with PND-induced apoptosis. Data from this study suggests that PND induces cellular toxicity and genetic perturbations which can alter the normal cellular and physiological functioning in rats.

Thiamethoxam induced hepatotoxicity and pro-carcinogenicity in rabbits via motivation of oxidative stress, inflammation, and anti-apoptotic pathway

Thiamethoxam (TMX) is a non-mutagenic neonicotinoid insecticide that is widely used to combat different types of insects. The hepatotoxicity and carcinogenicity of TMX have been approved previously in mice but not in rats. However, the TMX-induced hepatotoxic and pro-carcinogenic effects on rabbits remain unclear. The present study elucidated the roles of oxidative stress, pro-inflammatory cytokines, and apoptosis-related genes in the hepatotoxic and carcinogenic effects of TMX on rabbits. Sixteen male rabbits were equally divided into two groups; eight rabbits orally treated with TMX at a dose of 250 mg/kg b.w for 90 successive days. Hepatotoxic effects of TMX were evidenced by attenuation of liver enzyme activities, elevation of bilirubin levels, and alterations in the hepatic architecture, including hepatocyte death by necrosis and apoptosis, lymphocyte infiltration and fibrosis. TMX induced oxidative stress, as evidenced by the significant increases in malondialdehyde levels and antioxidant enzyme (glutathione transferase and catalase) activities along with a decrease in glutathione levels. TMX also up-regulated the mRNA levels of interleukin-6 (1.6-fold) and B cell lymphoma-2 (1.8-fold) and down-regulated the mRNA level of the tumor necrosis factor-α (0.8-fold), indicating its effects on cell survival and proliferation through the inhibition of apoptosis. Interestingly, the elevated level of carcinoembryonic antigen and the appearance of ground glass-like hepatocytes suggested that TMX exerted a pro-carcinogenic effect. In conclusion, TMX exerts potentially hepatotoxic and pro-carcinogenic effects on rabbits by modulating oxidative/antioxidative status and pro-inflammatory cytokine production, inhibiting apoptosis and activating cell survival pathways.

The acute and chronic toxic effect of cypermethrin, propetamphos, and their combinations in rats

This study was aimed at determining the acute and chronic toxic effects of cypermethrin, propetamphos, and combined cypermethrin and propetamphos. Four groups, each comprising 10 animals, were established for the acute (a) and chronic (b) toxicity trials, and in total, 80 male Wistar albino rats were used. In the acute toxicity trial, the first group was maintained for control purposes, and groups 2a, 3a, and 4a were administered only once with 80 mg/kg.bw of cypermethrin, 25 mg/kg.bw of propetamphos and 80 mg/kg.bw of cypermethrin combined with 25 mg/kg.bw of propetamphos, respectively, by gavage directly into the stomach. In the chronic toxicity trial, the first group was also maintained for control purposes, while groups 2b, 3b, and 4b were administered daily with 12 mg/kg.bw of cypermethrin, 4 mg/kg.bw of propetamphos, and 12 mg/kg.bw of cypermethrin combined with 4 mg/kg.bw of propetamphos respectively, by gavage directly into the stomach for 60 days. Blood and tissue (liver, kidney, brain, spleen, and testis) samples were taken 24 h after pesticide administration in the acute toxicity trial and at the end of day 60 in the chronic toxicity trial. Oxidative stress (MDA, NO, SOD, CAT, GSH-Px, and G6PD) parameters, serum biochemical parameters (glucose, triglyceride, cholesterol, HDL, LDL, BUN, creatinine, AST, ALT, ALP, protein, and albumin) and hepatic drug-metabolizing parameters (CYP2E1, CYPB5, CYTC, GST, and GSH) were investigated in the samples. When administered either alone or in combination, both pesticides inhibited the antioxidant enzymes and increased MDA and NO levels. For the drug-metabolizing parameters investigated, particularly in the chronic period, either increase (CYP2E1, CYPB5, and CYTC) or decrease (GST and GSH) was observed. Furthermore, some negative changes were detected in the serum biochemical parameters. In result, cypermethrin and propetamphos combinations and long-term exposure to these combinations produced a greater toxic effect than the administration of these insecticides alone. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1415-1429, 2016.

Diastereomeric and enantiomeric selective accumulation of cypermethrin in the freshwater mussel Unio gibbus and its effects on biochemical parameters

Synthetic pyrethroids are a family of chiral pesticides with a large number of stereoisomers. Cypermethrin (CYP) is used in a variety of agricultural crops, but also has public health and veterinary uses. In this work, the freshwater mussel (Unio gibbus) was chosen to evaluate the stereoselectivity of CYP through the use of gas chromatography with mass-spectrometry. The effects of CYP on mussels were examined by measuring neurotoxicity and oxidative stress biomarkers during its uptake. The investigation was performed under laboratory conditions using nominal CYP concentrations C1=100 μg/L and C2=150 μg/L over 96 h. Preferential bioaccumulation of cis-CYP isomers was observed. Furthermore, enantiomeric characterization revealed enantioselective accumulation, most probably related to mussel metabolism. Antioxidant enzyme activities (superoxide dismutase (SOD), and catalase (CAT)), and levels of reduced glutathione (GSH) and malondialdehyde (MDA) were determined in digestive gland after 4 days of exposure. CYP significantly inhibited acetylcholine esterase activity, by 51% and 57%, respectively, in mussels treated with 100 and 150 μg/L doses. The highest and lowest CYP concentrations elicited an increase of 67 and 63%, respectively, in SOD activity compared to the controls, while CAT activity was increased by 65 and 73%. A statistically significant decrease in GSH levels (40%) was observed only with the highest CYP concentration tested (150 μg/L). In addition, lipid peroxidation was significantly higher (67%) than in controls. These results provided information on CYP-enantioselective uptake and potential biomarkers that could be effectively applied for the biomonitoring of freshwater ecosystem.

The toxic effect of cypermethrin, amitraz and combinations of cypermethrin-amitraz in rats

In this study, the effects of cypermethrin (CYP), amitraz (AMT) and combined cypermethrin-amitraz (CYP-AMT) on some serum biochemical, oxidative stress and drug-metabolising parameters were investigated in male Wistar albino rats. CYP, AMT and combined CYP-AMT were administered at doses of 80 mg kg(-1) bw(-1) of CYP and 170 mg kg(-1) bw(-1) of AMT for 1 day (single dose), and at doses of 12 mg kg(-1) bw(-1) of CYP and 25 mg kg(-1) bw(-1) of AMT for 40 days by oral gavage. Oxidative stress (malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glucose-6-phosphate dehydrogenase (G6PD)), serum biochemical (glucose, triglyceride, cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), blood urea nitrogen (BUN), creatinine, asparatate amino transferase (AST), alanine amino transferase (ALT), alkaline phosphatase (ALP), total protein, albumin) in blood/tissues (liver, kidney, brain, spleen and testis) and hepatic drug-metabolising (cytochrome P450 2E1 (CYP2E1), NADH-cytochrome b5 reductase (CYPb5), NADPH-cytochrome c reductase/NADPH cytocrome P450 reductase (CYTC), glutathione S-transferase (GST), glutathione (GSH)) parameters were measured in liver samples taken on days 1 and 40. In result, it was determined that CYP, AMT and their combinations led to significant changes in the parameters investigated, and it was ascertained that long-term exposure to insecticides and the administration of insecticide combinations produced greater toxic effects in comparison with the administration of insecticides alone.

Quercetin protects HCT116 cells from Dichlorvos-induced oxidative stress and apoptosis

The present study was designed to assess the possible protective effects of Quercetin (QUER), a flavonoid with well-known pharmacological effects, against Dichlorvos (DDVP)-induced toxicity in vitro using HCT116 cells. The cytotoxicity was monitored by cell viability, reactive oxygen species (ROS) generation, anti-oxidant enzyme activities, malondialdehyde (MDA) production, and DNA fragmentation. The apoptosis was assessed through the measurement of the mitochondrial transmembrane potential (ΔΨm) and caspase activation. The results indicated that pretreatment of HCT116 cells with QUER, 2 h prior to DDVP exposure, significantly decreased the DDVP-induced cell death, inhibited the ROS generation, modulated the activities of catalase (CAT) and superoxide dismutase (SOD), and reduced the MDA level. The reductions in mitochondrial membrane potential, DNA fragmentation, and caspase activation were also attenuated by QUER. These findings suggest that dietary QUER can protect HCT116 cells against DDVP-induced oxidative stress and apoptosis.

Redox status in liver of rats following subchronic exposure to the combination of low dose dichlorvos and deltamethrin

Organophosphates and pyrethroids are widely used pesticides with prominent toxicity to humans. However, their joint toxicity has not been thoroughly investigated. In this study, we investigated the oxidative damages induced by low dose dichlorvos (DDVP) and deltamethrin (DM), the representative organophosphate and pyrethroid, respectively, and their mixtures in the liver of rats for 90 consecutive days. Two oxidative stress markers, malondialdehyde (MDA) and protein carbonyl (PCO) levels, were measured to reflect the extent of lipid peroxidation and protein oxidation, respectively. DDVP, DM, and their mixtures induced levels of MDA and PCO dose-dependently, although no toxic signs and pathological changes of liver were found in the rats following 90-day exposure. DDVP and DM induced greater increase of MDA than PCO, which indicated that lipids were particularly sensitive to the oxidative damage. We found that DDVP, DM and their mixtures could inhibit the activity of two antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). The effects of DM on SOD activity, lipid peroxidation and protein oxidation were greater than those of DDVP. The combined effect of DDVP and DM was lower than the sum of their individual effects. Thus the interaction between dichlorvos and deltamethrin may be antagonistic on the induction of oxidative stress in rat liver.

Dietary exposure to continuous small doses of α-cypermethrin in the presence or absence of dietary curcumin does not induce oxidative stress in male Wistar rats

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α-Cypermethrin induces toxicity in rats when administered at single high doses.

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In humans, exposure is primarily via contaminated food.

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Continuous dietary exposure does not cause oxidative stress or hepatotoxicity in rats.

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Single-dose gastric-intubation studies may have overestimated its toxicity in rats.

α-Cypermethrin is a widely used insecticide and, at high doses, induces oxidative stress in mammals. Curcumin is an antioxidant phytochemical commonly used for food coloring and flavoring. We aimed to investigate the effects of continuous dietary exposure to low doses of α-cypermethrin, as is the case in exposed humans, on oxidative stress and its potential prevention by dietary curcumin. Four groups of ten male Wistar rats were ad libitum-fed a control diet or identical diets fortified with α-cypermethrin (350 mg/kg diet), curcumin (1000 mg/kg diet), or α-cypermethrin and curcumin (350 and 1000 mg/kg diet, respectively) for 7 weeks. α-Cypermethrin accumulated in adipose tissues and was detectable in kidney, liver, and brains. Dietary α-cypermethrin did not alter concentrations of malondialdehyde, ascorbic and uric acid, retinol, liver damage markers, or the activities of CAT and SOD, but reduced vitamin E in blood. α-Cypermethrin did not affect malondialdehyde or reduced glutathione concentrations in any of the tissues, but significantly increased glutathione disulfide in kidney and subcutaneous adipose tissue. In conclusion, dietary exposure to small doses of α-cypermethrin did not induce oxidative stress in rats and may be less toxic than exposure to comparable quantities administered as single high doses by gastric intubation.

Allethrin induced toxicity in the male reproductive tract of rats contributes to disruption in the transcription of genes involved in germ cell production

Pyrethroids are known to be neurotoxic. However, their toxic effects including that of allethrin on the male reproductive tract are not elucidated. Adult male rats were treated orally with 25, 50, 100, and 150 mg/kg body weight allethrin every day for 60 days. Lipid peroxidation was increased (p < 0.001) in the caput, cauda, and testes. Nitric oxide production was increased (p < 0.001) in the caput, but unaltered in the cauda and testes. The activities of catalase, glutathione peroxidase, glutathione-S-transferase, and superoxide dismutase were decreased in the caput and cauda where as a decrease was observed in the testis obtained from allethrin treated rats. In the epididymides and testes, damage to tubular architecture, congestion, degeneration of epithelial cell lining, intestinal edema, and presence of dead or degenerating spermatids were observed in a dose dependent manner. The expression profile of genes involved in spermatogenesis (Tgf-beta1), sperm maturation (Spag11e), and sperm function (Defb22) were reduced (p < 0.001) in allethrin rats. The expression of p53 gene was decreased and increased phosphorylation of MAPK (p42/p44) expression was observed the male reproductive tract tissues of allethrin treated rats. Although earlier studies have reported the effects of allethrin inhalation because of the use of mosquito coils and vaporizers, our results for the first time prove that oral exposure to allethrin could affect fertility and may contribute to deregulation of cell cycle in the male reproductive tract.

Diphenyl diselenide protects against metabolic disorders induced by acephate acute exposure in rats

The present study investigated the effect of diphenyl diselenide [(PhSe)2 ] on metabolic disorders induced by acephate acute exposure in rats. We also investigated a possible mechanism of action of (PhSe)2 against hyperglycemia induced by acephate. (PhSe)2 was administered to rats at a dose of 10 or 30 mg/kg by oral gavage (p.o.) 1 hour prior to acephate administration (140 mg/kg; p.o.). Glucose and corticosterone levels as well as the lipid status were determined in plasma of rats. Cardiovascular risk factors and the atherogenic index were calculated. Glycogen levels as well as tyrosine aminotransferase (TAT) and glucose-6-phosphatase (G6Pase) activities were determined in livers of rats. Cerebral acetylcholinesterase (AChE) activity was assayed. Acephate induced an increase in glucose and corticosterone levels as well as in TAT and G6Pase activities. AChE activity was inhibited by acephate. Triglyceride (TG) levels and the cardiovascular risk factor TG/high-density lipoprotein-cholesterol (HDL) were increased by acephate. (PhSe)2 was effective against the metabolic disorders induced by acephate acute exposure in rats.

Amelioration of prallethrin-induced oxidative stress and hepatotoxicity in rat by the administration of Origanum majorana essential oil

This study was carried out to evaluate the adverse effects of exposure to prallethrin on oxidant/antioxidant status and liver dysfunction biomarkers and the protective role of Origanum majorana essential oil (EO) in rat. Male rats were divided into 4 groups: (i) received only olive oil (ii) treated with 64.0 mg/kg body weight prallethrin (1/10 LD₅₀) in olive oil via oral route daily for 28 days, (iii) treated with 64.0 mg/kg body weight prallethrin (1/10 LD₅₀) and EO (160 μL/kg b.wt.) in olive oil and (iv) received EO (160 μL/kg b.wt.) in olive oil via oral route twice daily for 28 days. Prallethrin treatment caused decrease in body weight gain and increase in relative liver weight. There was a significant increase in the activity of serum marker enzymes, aspartate transaminase, alanine transaminase, and alkaline phosphatase. It caused increase in thiobarbituric acid reactive substances and reduction in the activities of superoxide dismutase, catalase, and glutathione-S-transferase in liver. Consistent histological changes were found in the liver of prallethrin treatment. EO showed significant protection with the depletion of serum marker enzymes and replenishment of antioxidant status and brought all the values to near normal, indicating the protective effect of EO. We can conclude that prallethrin caused oxidative damage and liver injury in male rat and co-administration of EO attenuated the toxic effect of prallethrin. These results demonstrate that administration of EO may be useful, easy, and economical to protect human against pyrethroids toxic effects.

The effect of chlorpyrifos on isolated thoracic aorta in rats

This study investigated the effect of chlorpyrifos on thoracic aorta and on the level of NO in plasma and aorta. The effect of chlorpyrifos on thoracic aorta in organ bath was determined in 10 rats. Another 45 rats were assigned to 3 groups with 15 rats each: control group 1 received distilled water, control group 2 was given corn oil, and the last group was given 13.5 mg/kg chlorpyrifos dissolved in corn oil every other day for 8 weeks orally. Chlorpyrifos (10⁻¹⁰ M–10⁻⁵ M) showed no effect on isolated thoracic aorta. Plasma AChE activity was decreased, while LDH, ALT, GGT, and AST activities were increased in chlorpyrifos group compared to control groups. Plasma NO level was increased in chlorpyrifos group compared to control groups. iNOS expression was present in all groups in the cytoplasm of the endothelia and in the smooth muscle cells of aorta. According to semiquantitative histomorphological analysis, iNOS immunopositive reactions were seen in the decreasing order in chlorpyrifos, control 2, and control 1 groups. eNOS immunopositive reactions were observed in the endothelial cell cytoplasm, rarely in the subintimal layer, and the smooth muscle cells of aorta. There were no differences among the groups in terms of eNOS immunostaining. In conclusion, chlorpyrifos induced NO production in aorta following an increase in NOS expression.

Subacute oral toxicity of combinations of selected synthetic pyrethroids, piperonyl butoxide, and tetramethrin in rats

In this study, 70 Wistar rats were randomly divided into seven equal groups (six experimental and one control), which consisted of animals belonging to both sexes. Different combinations of insecticides were administered daily to the experimental groups (group 1: cypermethrin + piperonyl butoxide (PBO); group 2: alphacypermethrin + PBO; group 3: deltamethrin + PBO; group 4: cypermethrin + PBO + tetramethrin; group 5: alphacypermethrin + PBO + tetramethrin; and group 6: deltamethrin + PBO + tetramethrin) for 28 days. During the study period, mortality and serious clinical findings were not observed in any animal. However, feed consumptions decreased in groups 1 and 3 ( p < 0.05). Red blood cells, white blood cells, and hemoglobin levels, especially in cypermethrin and alphacypermethrin groups (groups 1, 2, and 4), were found to be higher than the control group ( p < 0.05). Furthermore, biochemical changes related to liver, kidney functions, and protein metabolism occurred in males of almost all the groups. Relative liver and kidney weights of the male animals increased in the cypermethrin and alphacypermethrin groups ( p < 0.05). The most common finding observed during the histopathological examination of all the experimental groups was centrilobular degeneration in the liver. It was concluded that although clinical symptoms were not observed, synthetic pyrethroid, synergist, and knockdown agent combinations might cause serious abnormalities when administered in certain doses in mammalians.

The antioxidant effect of wheat germ oil on subchronic coumaphos exposure in mice

Forty-eight male Balb/C mice, allocated to 4 equal groups, constituted the material of the study. The first group was maintained as the control group and was administered solely with a vehicle, which was used to dissolve coumaphos in the third and fourth groups. The second group was administered with 1.5 ml/kg.bw/day (∼1400 mg/kg.bw/day) of wheat germ oil. The third group received 5.5mg/kg.bw/day (1/10 LD50(oral)) of coumaphos. Finally, the fourth group was given both coumaphos and wheat germ oil at the doses indicated above. In all groups, the compounds were given directly into the stomach using a gastric tube, and treatment was continued for a period of 45 days. At the end of the 45th day, the liver, lungs, kidneys, brain, heart and spleen were extirpated in all of the animals. Tissue homogenates prepared from the tissue specimens were analysed for malondialdehyde (MDA) levels and catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. In conclusion, it was determined that coumaphos led to adverse alterations in the majority of the oxidative stress markers investigated. The administration of wheat germ oil alleviated the coumpahos-induced adverse effects detected in the tissues examined.

Developmental toxicity of cypermethrin in embryo-larval stages of zebrafish

Cypermethrin, a type II pyrethroid insecticide, is widely used throughout the world in agriculture, forestry, horticulture and homes. Though the neurotoxicity of cypermethrin has been thoroughly studied in adult rodents, little is so far available regarding the developmental toxicity of cypermethrin to fish in early life stages. To explore the potential developmental toxicity of cypermethrin, 4-h post-fertilization (hpf) zebrafish embryos were exposed to various concentrations of cypermethrin (0, 25, 50, 100, 200 and 400 μg L⁻¹) until 96 h. Among a suite of morphological abnormalities, the unique phenotype curvature was observed at concentrations as low as 25 μg L⁻¹. Studies revealed that 400 μg L⁻¹ cypermethrin significantly increased malondialdehyde production. In addition, activity of antioxidative enzymes including superoxide dismutase and catalase were significantly induced in zebrafish larvae in a concentration-dependent manner. To further investigate the toxic effects of cypermethrin on fish, acridine orange (AO) staining was performed at 400 μg L⁻¹ cypermethrin and the result showed notable signs of apoptosis mainly in the nervous system. Cypermethrin also down-regulated ogg1 and increased p53 gene expression as well as the caspase-3 activity. Our results demonstrate that cypermethrin was able to induce oxidative stress and produce apoptosis through the involvement of caspases in zebrafish embryos. In this study, we investigated the developmental toxicity of cypermethrin using zebrafish embryos, which could be helpful in fully understanding the potential mechanisms of cypermethrin exposure during embryogenesis and also suggested that zebrafish could serve as an ideal model for studying developmental toxicity of environmental contaminants.

Cypermethrin exposure during puberty induces oxidative stress and endocrine disruption in male mice

Cypermethrin (CYP) is one of the most common contaminants in the ecosystem. The effects of CYP exposure on the induction of oxidative stress and endocrine disruption were studied in adolescent male ICR mice. The hepatic activities of antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase (CAT) and total antioxidant capacity (T-AOC) increased significantly after 3 weeks (postnatal day 21-42) of oral administration of 20 mg kg(-1) CYP. In accordance with the enzyme activities, the mRNA levels for the genes encoding these antioxidant proteins, such as Sod1, Sod2, Gpx1 and Gpx2, were also up-regulated significantly in the 10 and 20 mg kg(-1) CYP treatment groups. Furthermore, we also found that the 3-week oral administration of CYP decreased transcription levels of key genes in pathways of cholesterol synthesis and transport and testosterone synthesis including HMG-CoA synthase, steroidogenic acute regulatory protein (StAR) and cytochrome P450 17α-hydroxysteroid dehydrogenase (P450 17α in the liver and testes. Serum testosterone levels also decreased significantly in mice after treatment with 20 mg kg(-1) CYP. Taken together, the results indicated that CYP can induce endocrine disruption in adolescent mice. The findings will be helpful in elucidating the mechanism of toxicity induced by CYP in adolescent mice.

Effect of propetamphos on the male rats reproductive system

The present study aimed at defining the testicular toxicity of propetamphos. Mature male albino rats (5-6 months old) were treated with propetamphos orally at doses of 0, 0.18, 0.38, 0.75, 1.5 and 3mg/kg/day for 60 consecutive days. Propetamphos at a dose of 0.38 mg/kg/day significantly reduced the sperm motility only. At 0.75 mg/kg/day sperm count, sperm motility, plasma testosterone level and activity of sorbiol dehydrogenase (SDH) were significantly reduced and sperm morphological abnormalities were significantly increased. At 1.5mg/kg/day weight of testes, seminal vesicle and epididymis were reduced dose dependently whereas, at 3mg/kg/day, weight of prostate gland and activities of acid phosphatase (ACP) and glucose-6-P-dehydrogenase (G6PDH) were decreased significantly. On histopathological examination indicated toxicity of propetamphos on testes depending on dose and observed at doses higher than 0.38 mg/kg/day. These results indicate testicular toxicity of propetamphos at dose of 0.38 mg/kg/day or higher in male albino rats.

Oxidative stress induced by lambda-cyhalothrin (LTC) in rat erythrocytes and brain: Attenuation by vitamin C

The objective of this study was to investigate the propensity of lambda-cyhalothrin (LTC) to induce oxidative stress in blood and brain of male Wistar rats and its possible attenuation by vitamin C. Rats were randomly divided into four groups: group I served as control rats. group II was treated daily with 200mgvit C/(kgbw) administered by intraperitoneal way. Rats of group III have received orally 668ppm LTC. Animals of group IV were treated with LTC and vitamin C. A decrease of some hematologic parameters (RBC, Hb, Ht: p<0.01) and a significant increase of MDA levels (p<0.05) in erythrocytes and brain were observed in LTC group compared to controls. Antioxidant enzyme activities in both tissues were modified in LTC group compared to controls. Administration of vitamin C ameliorated these parameters. Our results indicated the potential effects of LTC to induce oxidative damage in tissues and the ability of vitamin C to attenuate LTC-induced oxidative damage.