Methomyl induced hematological and biochemical alterations – protection by vitamin E

Betaine alleviates methomyl-triggered oxidative stress-mediated cardiopulmonary inflammation in rats through iNOS/Cox2 and Nrf2/HO1/Keap1 signaling pathway

Methomyl (MET), a universally used insecticide, has many adverse effects on various organs in both humans and animals including the liver, kidneys, and heart. Betaine (BET), a natural antioxidant, has a protective role against many toxicants-induced cardiovascular disorders. The present study was designed to elucidate the molecular mechanistic way underlying the mitigating effect of BET against MET-induced cardiopulmonary injury and inflammation in rats. Four groups of rats were used and orally administered the consequent materials daily for 28 days: normal saline, BET (250 mg/kg bwt), MET (2 mg/kg bwt), MET + BET. Blood and tissue (heart & lungs) samples were collected to assess the oxidative stress markers, lipid profile, biochemical markers, microscopic appearance, and inflammatory gene regulations. The results proved that MET induced oxidant/antioxidant imbalance, elevation of serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels, and deterioration in lipid profile. The histopathological inspection showed severe myocardial necrosis and interstitial pneumonia along with bronchitis and alveolar damage. There was a marked increase in the intensity of cyclooxygenase-2 (Cox-2) and inducible nitric oxide synthase (iNOS) immunostaining with marked upregulation of the transcriptase levels of keap-1gene and downregulation of nuclear factor erythroid 2-related factor-2 (Nrf-2) and heme oxygenase-1 (HO-1) genes in both heart and lung tissues of MET group. Otherwise, the coadministration of BET with MET markedly alleviated the abovementioned toxicological parameters. We can conclude that BET was able to reduce the MET-induced oxidative stress-mediated cardiovascular injury and pulmonary inflammation by modulating Keap-1/Nrf-2 signaling pathway and inactivating Cox-2 and iNOS expression which therefore reduced further cellular damage and inflammatory response.

Hyperglycemia enhances the generation of ROS and RNS that impair antioxidant power and cause oxidative damage in human erythrocytes

Hyperglycemia is a state in which excess glucose circulates in blood. Erythrocytes are in direct contact with this high glucose concentration and are greatly affected by it. We have examined the effect of hyperglycemic condition on isolated human erythrocytes under in vitro conditions. Erythrocytes were incubated with different concentrations of glucose (5, 15, 30, 45 mmol/L) for 24 h, and several biochemical parameters were determined. Treatment with high glucose concentrations increased heme degradation and methemoglobin level, while methemoglobin reductase activity was decreased. A significant increase in protein oxidation and lipid hydroperoxides with a decrease in total sulfhydryl content was seen. This suggested the generation of oxidative stress, which was confirmed by an enhanced production of reactive oxygen and nitrogen species. Hyperglycemia led to a significant decline in the antioxidant power of erythrocytes, lowering their ability to quench free radicals and reduce metal ions to lower oxidation states. The plasma membrane redox system was upregulated, while ascorbate free radical reductase activity was lowered. Glucose exposure inhibited the enzymes of glycolysis and hexose monophosphate shunt. Electron microscopy showed morphological changes resulting in the formation of echinocytes. Thus, the hyperglycemic condition generates reactive species that oxidize proteins, hemoglobin, and lipids; impair the total antioxidant capacity; and alter morphology in human erythrocytes.

Cadmium chloride generates cytotoxic reactive species that cause oxidative damage and morphological changes in human erythrocytes

Cadmium chloride (CdCl₂₎ is a widely used industrial compound that exhibits multiple organ toxicity. Cadmium is transported through blood where erythrocytes are exposed to its action. Here the effect of CdCl₂ on human erythrocytes was examined under in vitro conditions. Human erythrocytes were treated with 0.01-0.5 mM CdCl₂ for 24 h at 37 °C. Lysates were made from CdCl₂ treated and untreated (control) cells and used for further analysis. CdCl₂ treatment resulted in marked hemolysis of erythrocytes and oxidation of hemoglobin to methemoglobin. This will result in anemia and also reduce the oxygen carrying ability of erythrocytes. Hemoglobin oxidation was accompanied by degradation of heme and release of free ferrous iron moiety. Further analysis showed elevated lipid hydroperoxides and formation of advanced oxidation protein products along with reduction in total sulfhydryl content, indicating the generation of oxidative stress condition in the cell. Incubation of erythrocytes with CdCl₂ enhanced generation of reactive oxygen and nitrogen species, decreased the antioxidant power and inhibited pathways of glucose metabolism. Plasma membrane was damaged as indicated by enhanced osmotic fragility and inhibition of membrane bound enzymes. This was confirmed by electron microscopy which showed formation of echinocytes. These results show that CdCl₂ generates reactive species which impair the antioxidant system resulting in oxidative damage to erythrocytes.

Methomyl-induced nephrotoxicity and protective effect of curcumin in male rats

We investigated the ameliorative effect of the curcumin against methomyl-induced potential nephrotoxicity in Wistar albino male rats. In the present study, curcumin (100 mg kg^-1 bw), methomyl (0,8 mg kg^-1 bw) and methomyl plus curcumin were given to rats by oral for 28 days (for subacute examination). Concentrations of blood urea nitrogen, uric acid and creatinine in serum and malondialdehyde level and activities of antioxidant enzyme (superoxide dismutase, catalase, glutathione peroxidase and glutathione S transferase) and histopathological alterations in kidney tissues were studied. Methomyl caused an increment in the concentrations of blood urea nitrogen, creatinine, uric acid and MDA levels. In addition, methomyl caused a diminution in the activities of superoxide dismutase, catalase, glutathione peroxidase and glutathione S transferase. Tubular and glomerular degenerations occurred in the kidney tissues of methomyl-received rats. However, coadministration of curcumin with methomyl significantly minimized the adverse effects of methomyl on kidney function parameters, lipid peroxidation and antioxidant enzyme activities and histological structure of kidney tissue. The results showed that curcumin significantly mitigated methomyl-induced nephrotoxicity in rats.

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.

Short-term exposure of Balb/c mice to buprofezin insecticide induces biochemical, enzymatic, histopathologic and genotoxic damage in liver and kidney tissues

Buprofezin is a type-1 chitin synthesis inhibitor insecticide used to control hemipteran insects. It is generally considered safe for humans, but its persistent nature may become a health hazard if long-term exposure takes place. Adverse effects on mammals are remaining to be explored. The present study investigated buprofezin toxicity on liver and kidney tissues of Balb/c mice treated intraperitoneally with 4.0, 6.0 and 8.0 µg/kg b.w doses respectively for 24 h. Statistical analyses demonstrated increased activities (p < 0.05) of serum alanine aminotransferase, aspartate aminotransferase, creatinine and urea, ROS and TBARS (thiobarbutaric acid) in liver and kidney tissues. Concomitant significant decrease occurred in tissue total protein, antioxidants enzymes, the superoxide dismutase, catalase and peroxidase and non-enzymatic reduced glutathione. Significantly altered histomorphology of liver and kidney tissues revealed excessive tissue damage. Congestion, hepatocyte necrosis, decreases sinusoidal damage in liver, while in kidneys, glomerular shrinkage, capillary damage, widened Bowman's space and lumens of tubules and collecting ducts and necrosis of tubular epithelial cells were evident. TUNEL assay confirmed apoptosis, the Comet assay demonstrated DNA damage by an increase in the head length, tail length, comet length, tail moment and olive tail moment. The study concludes that buprofezin is highly toxic for mammalian tissues and warrants further biochemical, molecular and cellular studies.

Sublethal effects of pulp and paper mill effluent on two commonly cultured carps: a SEM- and EDS-based hematological biomarker analysis

Blood being a vehicle for the transport of industrial pollutants in living system, fish hematology is considered as potent biomarker. In the present study, we investigated respective sublethal effects of pulp and paper mill effluents on hematology of two commonly cultured carps, Cyprinus carpio and Ctenopharyngodon idella, using optical, scanning electron microscopy and energy-dispersive X-ray spectroscopy. Irrespective of species, results showed significant decrease in erythrocyte, hematocrit and hemoglobin contents while an increase in white blood cell counts (P < 0.05). We observed an increasing trend of MCV (170.0 ± 3.07 to 193.16 ± 2.5) and MCH (34.31 ± 1.89 to 38.71 ± 3.61) up to 28th day in C. carpio (P < 0.05), while, in C. idella, the highest percent increase in MCV (180.8 ± 2.19) and MCH (32.9 ± 0.62) was observed on seventh exposure day, which subsequently declined, respectively, to 173.1 ± 17.1 and 27.9 ± 2.45 on 28th day. Unlike C. carpio, significant and progressive MCHC declining trend (18.23 ± 0.28 to 16.13 ± 0.31) was observed in C. idella. The most commonly observed abnormalities under SEM include echinocytes, cytoplasmic blebbing, cytoplasmic ring, spherocytes, lobopodial projections and acanthocytes in red blood cells of exposed fishes. EDS further revealed the presence of aluminum, antimony, arsenic, cadmium, mercury, tungsten, zinc and titanium; some of these metals were not even detected in the effluent samples, suggesting the probable metal bio-concentration in fish tissue, and subsequent jeopardization is a major concern particularly in the industrial area. Our study further suggested the use of sensitive and specific techniques like SEM and EDS in fish hematological biomarker analysis along with the conventional approach.

1H-NMR-based metabolomic study on toxicity of methomyl and methidathion in fish

A ¹H-nuclear magnetic resonance (NMR) spectroscopy with multivariate analysis was applied to detect the toxicity of antiacetylcholinesterase insecticides, methomyl (methyl (1E)-N-(methylcarbamoyloxy)ethanimidothioate) and methidathion (3-(dimethoxyphosphinothioyl sulfanylmethyl)-5-methoxy-1,3,4-thiadiazol-2-one), using zebrafish (Danio rerio) and Chinese bleak (Aphyocypris chinensis). Generally, methomyl and methidathion have been believed not to highly accumulate in fish tissues. However, these pesticides showed their toxicity by altering patterns of whole-body metabolites in neurotransmitter balance, energy metabolism, oxidative stress, and muscle maintenance in low concentrations. We used Pearson correlation analysis to contextualize the metabolic markers in pesticide treated groups. We observed that the positive correlations of choline with acetate and betaine in untreated control were shifted to null correlations showing acetylcholinesterase specific toxicity. This research demonstrated the applicability and potential of NMR metabolomics in detecting toxic effects of insecticide with a modicum of concentrations in aquatic environment.

Alteration of lipid status and lipid metabolism, induction of oxidative stress and lipid peroxidation by 2,4-dichlorophenoxyacetic herbicide in rat liver

This study aims to investigate the effects of the 2,4-dichlorophenoxyacetic herbicide (2,4-D) on plasma lipids, lipoproteins concentrations, hepatic lipid peroxidation, fatty acid composition and antioxidant enzyme activities in rats. Animals were randomly divided into four groups of 10 each: control group and three 2,4-D-treated groups G1, G2 and G3 were administered 15, 75 and 150 mg/kg/BW/d 2,4-D by gavage for 28 d, respectively. Results showed that 2,4-D caused significant negative changes in the biochemical parameters investigated. The malondialdehyde level was significantly increased in 2,4-D-treated groups. Fatty acid composition of the liver was also significantly changed with 2,4-D exposure. Furthermore, the hepatic antioxidant enzyme activities were significantly affected. Finally, 2,4-D at the studied doses modifies lipidic status, disrupt lipid metabolism and induce hepatic oxidative stress. In conclusion, at higher doses, 2,4-D may play an important role in the development of vascular disease via metabolic disorder of lipoproteins, lipid peroxidation and oxidative stress.

Protective effects of vitamin C and selenium supplementation on methomyl-induced tissue oxidative stress in adult rats

Methomyl (MET) is used worldwide in agriculture and health programs. Besides its advantages in the agriculture, it causes several toxic effects. The objective of this study was to examine the potential ability of vitamin C and/or selenium (Se), to alleviate the oxidative damage parameters, against MET-induced changes in blood biochemical markers and oxidative damage in liver and kidney of male Wistar rats. The animals were randomized into five groups of eight each: group I served as control rats; group II received MET (8 mg/kg body weight (BW)) in drinking water; group III received both MET and vitamin C (200 mg/kg BW; by intraperitoneal injection); group IV received both MET and Se (0.6 mg/100 g BW). Animals of group V were treated with MET, vitamin C and Se. A significant increase in the levels of hepatic markers enzymes (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase) was determined. Furthermore, renal markers such as urea and creatinine were increased in MET-treated rats. Additionally, serum cholesterol and triglycerides were significantly enhanced. Exposure of rats to MET caused significant increase in malondialdehyde levels, thus causing a drastic alteration in antioxidant defense system, particularly in the activities of catalase and glutathione- S-transferase and glutathione peroxidase. However, simultaneous supplementation with vitamin C and Se restored these parameters partially. In conclusion, the results of the current study revealed that MET-induced toxicity caused perturbations of some biochemical parameters, lipid peroxidation and alterations in the antioxidant enzymes in liver and kidney homogenates. Administration of vitamin C and Se exhibited protective effect by inhibiting MET-induced toxicity in liver and kidney.

Biochemical and histopathological changes induced by different time intervals of methomyl treatment in mice liver

The present study was designed to evaluate the toxic effects induced by different time intervals of methomyl exposure on liver antioxidant defense system, oxidative stress, liver function biomarkers and histopathology in CD-1 mice. Ten male mice per group were assigned to one of four treatment groups. Group one served as control while group 2, 3 and 4 were orally treated with one mg methomyl/kg BW for 10, 20 and 30 days, respectively. Results obtained showed that methomyl significantly induced TBARS and decreased the activity of antioxidant enzymes, glutathione S-transferase, superoxide dismutase and catalase and the levels of reduced glutathione in mice liver. Aminotransferases and alkaline phosphatase activities were significantly decreased in liver due to methomyl administration, while the activities of these enzymes were significantly increased in serum. In addition, liver lactate dehydrogenase activity was significantly increased. On the contrary, methomyl treatment caused a significant decrease in liver acid phosphatase. The histology of mice liver treated with methomyl for 10, 20 and 30 days of duration showed dilation of central vein, sinusoids between hypertrophied hepatocytes and nuclear degeneration with mononuclear cell infiltration. In conclusion, exposure to methomyl induced toxicity and oxidative stress in mice liver via free radicals mechanism. Also, methomyl might have affected cell metabolism, cell membrane permeability and the detoxification system in liver.