Effects of diazinon at different doses on rat liver and pancreas tissues

Diazinon is one of the most widely used organophosphates in agriculture. Toxic effects of diazinon are due to the inhibition of acetylcholinesterase, an enzyme needed for proper nervous system function. This study was designed to investigate the effects of diazinon at different doses on pancreas and liver tissues and in which dose level diazinon shows its effects. Sixty male Wistar albino rats were included in this study. Animals were initially divided into control and diazinon given groups. There were 10 animals in the control group and 50 animals in diazinon administered group. The latter was divided into five equal subgroups: 25, 50, 100, 200 and 300 mg/kg of diazinon administered groups. Control group was given only saline. All animals in 300 mg/kg diazinon group died. After 24 h, rats were sacrificed under ether anesthesia. Tissue and blood samples were taken for biochemical and histopathological analysis. Sample tissues were examined under light microscope. In biochemical analysis, AST, ALT, LDH, amylase and lipase enzyme activities were measured. One-way ANOVA test was used to compare the groups. In 200 mg/kg diazinon given group, it has been observed some histopathological changes in pancreas and liver tissues. Cholinesterase activities were significantly decreased and alkaline phosphatase levels were increased in all diazinon given groups, when compared with the controls. There was statistically significant difference between the control and diazinon given groups by means of serum amylase, lipase, ALT and AST activities (p < 0.05). LDH activities were significantly increased in 100 and 200 mg diazinon given groups, when compared with the controls (p < 0.05). Histopathological changes were observed only in 200 mg diazinon given group. This evidence suggest that diazinon effect is dose dependent and this is possibly 10-15% of the LD₅₀ dose (200 mg/kg), which cause acute pancreatitis and histopathological changes in liver.     

Acute toxicity of organophosphorous pesticide diazinon and its effects on behavior and some hematological parameters of fingerling European catfish (Silurus glanis L.)

Diazinon is commonly used for pest control in the agricultural fields surrounding freshwater reservoirs. So this study was conducted to determine the acute toxicity of this organophosphorous pesticide, contaminating aquatic ecosystems as a pollutant, and its effects on behavior, and some hematological parameters of fingerling European catfish, Silurus glanis. Diazinon was applied at concentrations of 1, 2, 4, 8, 16, 32, and 64 mg L⁻¹. The water temperature in the experimental units was kept at 16 ± 1 °C. The number of dead fishes significantly increased in response to diazinon concentrations 2-64 mg L⁻¹ (p < 0.05). With increasing diazinon concentrations, the fishes exposed duration 1 to 96 h significantly increased the number of dead fishes (p < 0.05 for each cases). The 1, 24, 48, 72, and 96 h LC₅₀ values (with 95% confidence limits) of diazinon for fingerling European catfish were estimated as 14.597 (12.985-16.340), 12.487 (11.079-14.471), 8.932 (7.907-10.348), 6.326 (no data because of p > 0.05), and 4.142 (no data because of p > 0.05) mg L⁻¹, respectively. Compared to the control specimens, fish after an acute exposure to diazinon was significantly lower erythrocyte, leukocyte, hemoglobin, hematocrit, MCV, MCH, and MCHC values (p < 0.05). In addition, it was also showed a significantly negative correlation between these hematological parameters and exposure times of diazinon (p < 0.01).     

Effects of diazinon on biochemical parameters of blood in rainbow trout (Oncorhynchus mykiss)

Existence of diazinon, an organophosphorous pesticide, in river waters of Iran near rice paddy fields has been reported by some authors. The present research aimed to determine the acute toxicity and evaluate the effect of sub-lethal concentrations of diazinon on some biochemical parameters of rainbow trout, Oncorhynchus mykiss after 7, 14 and 28 days. No significant differences were observed in the plasma levels of creatinine among the treatment groups at different sampling intervals. Acetylcholinesterase activity and the levels of total protein, albumin as well as globulin in plasma were significantly reduced at both concentrations tested (p < 0.05). Lactate dehydrogenase activity was only decreased on 7th day in 0.1 mg/L diazinon treatment (p < 0.05). Creatine kinase activity was significantly lower in 0.1 mg/L diazinon group at 14th and 28th sampling periods, whereas its activity significantly increased in fishes exposed to 0.2 mf/L diazinon only on 7th day (p < 0.05). Aspartate aminotransferase, alanine aminotransferase activities and glucose levels in diazinon treated groups were significantly higher than the controlled group at experimental periods (p < 0.05). In conclusion, long-term exposure to diazinon at sub-lethal concentrations induced biochemical alterations in rainbow trout, and offers a simply tool to evaluate toxicity-derived alterations.     

Protection by cAMP and cGMP phosphodiesterase inhibitors of diazinon-induced hyperglycemia and oxidative/nitrosative stress in rat Langerhans islets cells: Molecular evidence for involvement of non-cholinergic mechanisms

The objective of this study was to study the effects of acute administration of diazinon alone or in combination with two phosphodiesterase (PDE) inhibitors with selectivity to cAMP and cGMP (theophylline and sildenafil, respectively) on oxidative/nitrosative stress biomarkers, including nitric oxide (NO), lipid peroxides (TBARS), total antioxidant power (TAP), and concentration of tumor necrosis factor (TNF-α) in isolated Langerhans islets, plasma glucose and insulin levels, and the activity of plasma cholinesterase (ChE). Examination by different doses of diazinon (15, 30, and 60 mg/kg) in single administration lead us to choose diazinon (30 mg/kg) in combination therapies. Theophylline and sildenafil were used at doses of 25 and 5 mg/kg, respectively. In all diazinon-treated groups, plasma ChE activity and plasma insulin level were significantly decreased and plasma glucose concentration and Langerhans islets TNF-α, TBARS, and NO levels were significantly increased in comparison to controls. The TAP did not change in comparison to control. In combination therapy, both theophylline and sildenafil restored diazinon-induced changes in plasma glucose concentration, Langerhans islets TNF-α, NO, and TBARS concentrations but Langerhans islets TAP, plasma insulin, and ChE levels. It is concluded that diazinon stimulates oxidative/nitrosative stress in Langerhans islets that results in hyperglycemia due to insufficiency of insulin. Altered glucagons/insulin ratio, activated hepatic glucose production/release, and insulin resistance are possible mechanisms. The protective effects of cAMP and cGMP PDE inhibitors in restoration of diazinon-induced oxidative/nitrosative stress and hyperglycemia stress back to their antioxidant potentials that seem to be independent of ChE inhibition.     

Acute toxicity of diazinon on the common carp (Cyprinus carpio L.) embryos and larvae

In the present study, the toxic effects on the embryos and larvae of the common carp were used as a model to investigate the organophosphorus pesticide, diazinon, which contaminates aquatic ecosystems. Data obtained from the diazinon acute toxicity tests were evaluated using the Probit Analysis Statistical Method. The control and six test experiments were repeated five times. The number of dead embryos significantly increased in response to diazinon concentrations 0.25, 0.5, 1, 2, 4, and 8 mg L⁻¹ (p < 0.05 for each case). The 48 h LC₅₀ value (with 95% confidence limits) of diazinon for common carp embryos was estimated at 0.999 (0.698-1.427) mg L⁻¹. Dose-response decreases in hatching success were recorded as 84.60, 75.2, 54.1, 31.0, 6.0, and 0.0%, respectively (p < 0.05). The number of dead larvae significantly increased with increasing diazinon concentrations exposed for 24-96 h (p < 0.05). The 24, 48, 72, and 96 h LC₅₀ values (with 95% confidence limits) of diazinon for common carp larvae were estimated at 3.688 (2.464-8.495), 2.903 (2.019-5.433), 2.358 (1.672-4.005), and 1.530 (1.009-3.948) mg L⁻¹, respectively. There were significant differences in the LC₅₀ values obtained at different exposure times (p < 0.05). The results of the study suggest that low levels (0.25 mg L⁻¹) of diazinon in the aquatic environment may have a significant effect on the reproduction and development of carp.     

The effects of organophosphate insecticide diazinon on malondialdehyde levels and myocardial cells in rat heart tissue and protective role of vitamin E

Diazinon is an organophosphate insecticide has been used in agriculture and domestic for several years. Vitamin E (200 mg/kg, twice a week), diazinon (10 mg/kg, per day), and vitamin E (200 mg/kg, twice a week)+diazinon (10 mg/kg, per day) combination was given to rats orally via gavage for 7 weeks. Body and heart weights, malondialdehyde (MDA) level in heart tissue and ultrastructural changes in myocardial cells were investigated at the end of the 1st, 4th, and 7th weeks comparatively with control group. When diazinon-treated group was compared to control group body and heart weights were decreased significantly at the end of the 4th and 7th weeks. It was observed that, at the end of 1st, 4th, and 7th weeks there was a statistically significant increase in MDA levels when diazinon- and vitamin E +diazinon-treated groups were compared to control group. While at the end of the 1st week statistically significant changes were not being observed, at the end of 4th and 7th weeks statistically significant decrease was detected in MDA levels when vitamin E+diazinon-treated group was compared to diazinon-treated group. In our electron microscopic investigations, while vacuolization and swelling of mitochondria myocardial cells of diazinon-treated rats were being observed, swelling of several mitochondria were observed in vitamin E+diazinon-treated rats. We conclude that vitamin E reduces diazinon cardiotoxicity, but vitamin E does not protect completely.     

The effects of Saw palmetto on flumethrin-induced lipid peroxidation in rats

In the present study, 40 male Wistar albino rats were used and divided into 4 groups. The first group served as the control group; the second group was administered Saw palmetto extract at the dose of 20 mg/kg/bw; the third group was administered flumethrin at the dose of 15 mg/kg/bw; and the fourth group was administered a combination of 20 mg/kg/bw Saw palmetto extract and 15 mg/kg/bw flumethrin, for 21 days, orally. After the trial period, blood and tissue (liver, kidney and brain) samples were taken from the rats. Saw palmetto extract did not cause significant alterations in plasma and tissue malondialdehyde (MDA) levels, serum and tissue nitric oxide (NO) levels, erythrocyte and tissue superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities when compared to the controls (p > 0.05). Flumethrin led to increased plasma and tissue MDA levels, serum and tissue NO levels, tissue GSH-Px activities and decreased erythrocyte and tissue SOD and CAT activities, and erythrocyte GSH-Px activity, compared to the controls (p < 0.05). The flumethrin and Saw palmetto extract combination increased erythrocyte SOD activity and decreased brain GSH-Px activity as compared to flumethrin (p < 0.05). In conclusion, it was determined that Saw palmetto extract did not cause any negative effect on the prooxidant-antioxidant balance. While flumethrin stimulated lipid peroxidation; Saw palmetto extract at the dose of 20 mg/kg/bw did not exhibit enough antioxidant effect in rats.     

Changes in selected immunological parameters and antioxidant status of rainbow trout exposed to malachite green (Oncorhynchus mykiss, Walbaum, 1792)

In this study, the effects of malachite green on selected immunological parameters, oxidative stress and antioxidant status biomarkers in blood, liver, kidney, spleen and gill of rainbow trout, Oncorhynchus mykiss, was examined. During 5 days the malachite green was applied at concentrations of 1/15,000 and 1/150,000 for 30 s and 60 min, respectively. Immunological parameters (nitroblue tetrazolium (NBT) activity, total plasma protein (TP), total immunoglobulin (TI)) and biochemical parameters (lipid peroxidation (MDA), catalase (CAT) activity, reduced glutathione (GSH) levels) were evaluated after exposed to malachite green. It has been observed that NBT activity (p < 0.05, p < 0.001), total protein (p < 0.01, p < 0.001) and total immunoglobulin (p < 0.05, p < 0.001) levels were decreased compared with control group. In the rainbow tout exposed to malachite green duration 5 days significantly increased lipid peroxidation, which might be associated to decreased levels of reduced glutathione and catalase activity in the whole tissues of O. mykiss (p < 0.05, p < 0.01, p < 0.001 for each cases).     

Neurotoxicity in murine striatal dopaminergic pathways following co-application of permethrin, chlorpyrifos, and MPTP

The neurotoxic action of permethrin and chlorpyrifos on striatal dopaminergic pathways was investigated in C57BL/6 mice. Technical permethrin (50/50 ratio of cis and trans isomers, 200 mg/kg) and/or chlorpyrifos (75 mg/kg) were administered three times over a two-week period, with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 20 mg/kg) given on day one. Alterations in expression of α-synuclein, dopamine transporter (DAT), and tyrosine hydroxylase (TH) were analyzed at 1 or 28 days post-treatment. MPTP alone produced a long-lasting lesion in striatal dopaminergic pathways, with a depression of TH and DAT protein at both post-treatment times. Chlorpyrifos or permethrin alone had no effect on TH or DAT expression levels. No greater effect on protein expression was observed in mice treated with both MPTP and insecticides at 1 day post-treatment. However, by day 28 a significant reduction (p < 0.05) of TH and DAT was observed in the mice treated with MPTP, permethrin, and chlorpyrifos, compared with the mice given MPTP alone. Significant alteration (p < 0.05) of α-synuclein expression by MPTP (45% decrease) and permethrin (20% increase) occurred at 1 day post-treatment, but reverted to control levels by day 28. Parallel experiments with pure cis or trans isomers of permethrin (100 mg/kg), showed that each isomer caused about half the up-regulation of α-synuclein. These findings demonstrate that the co-application of pyrethroid or organophosphorus insecticides enhance the neurotoxicity of MPTP in C57BL/6 mice, and that a slowly developing neurotoxicity may occur after termination of high-dose exposure.     

Protective effects of caffeic acid phenethyl ester on rotenone-induced myocardial oxidative injury

Rotenone, an insecticide, causes toxicity through inhibition of mitochondrial electron transport chain at complex I and oxidative injury to the tissues. The aim of the present study was to determine in vivo effects of rotenone on myocardium and cardio-protective effects of caffeic acid phenethyl ester (CAPE), an antioxidant agent, against rotenone toxicity in rats. The rats were divided into three groups: untreated control, rotenone (2.5 mg/kg/day for 60 days, i.p.) and rotenone + CAPE groups. CAPE was administrated i.p. 10 μmol/kg/day for 62 days started two days before first dose rotenone injection. The malondialdehyde, nitric oxide levels and xanthine oxidase activity of rotenone group was significantly higher than control and rotenone + CAPE groups (p < 0.05). However, catalase activity in the rotenone group was decreased in comparison with the other groups (p < 0.05). The superoxide dismutase activity of rotenone group was insignificantly decreased compared to the others. In conclusion, rotenone caused lipid peroxidation in myocardial tissue and CAPE treatment prevented this rotenone-induced lipid peroxidation in rats. CAPE might be a cardio-protective agent against myocardial toxicities.     

Stimulation of insulin and glucagon synthesis in rat Langerhans islets by malathion in vitro: Evidence for mitochondrial interaction and involvement of subcellular non-cholinergic mechanisms

We examined the effects of malathion, an organophosphorus (OP) insecticide, on glucagon, C-peptide, and insulin content or secretion from isolated rat Langerhans islets in vitro. Islets were isolated from the pancreas of rats by standard collagenase digestion, separation by centrifugation, and hand-picking technique. Then islets were cultured in medium and supplemented with various concentrations of malathion (25, 125, and 625 μg/ml) for 1, 3, and 5 h. In vitro exposure to malathion increased insulin and C-peptide contents at doses of 25, 125, and 625 μg/ml following 5 h incubation as compared to control. All doses of malathion increased glucagon content after 3 and 5 h as compared to control. Increase of the glucagon content at all doses in the fifth hour was higher than that of third hour. Malathion also decreased 2.8 and 16.7 mM glucose-stimulated insulin secretion at all doses after 30 min as compared to control.It is concluded that malathion reduce insulin exocytose in a short time (first hour) but after a long time (e.g., 5 h), the content of insulin is increased by compensating mechanisms such as resynthesize of insulin or aggregation of insulin. The present in vitro study for the first time proposes the involvement of subcellular non-cholinergic mechanisms in malathion-induced changes in Langerhans islets insulin and glucagon.     

One-tenth dose of LC50 of 4-tert-butylphenol causes endocrine disruption and metabolic changes in Cyprinus carpio

Of the huge annual worldwide production (500,000 MT in 1997) of alkylphenol polyethoxylates (APEs) that are widely used as nonionic surfactants and anti-oxidants in variety of products, 60% ends up in water bodies. They undergo biodegradation to form octyl-, butyl-, and nonyl-phenols. This experiment evaluated effects of 4-tert-butyl phenol (4-TBP) in Cyprinus carpio, a projected candidate species in sewage fed fisheries. The 96th h LC₅₀ of 4-TBP was found to be 6.9 mg/L. Fishes were treated with 1/10th (0.69 mg/L), 1/5th (1.38 mg/L), and 1/3rd (2.3 mg/L) dose of LC₅₀. Whereas there was significant (P < 0.01) decrease in alkaline phosphatase [EC 3.1.3.1] and aspartate aminotransferase [EC 2.6.1.1] activity; alanine aminotranferase [EC 2.6.1.2] and acid phosphatase [3.1.3.2] (except decrease at 1/10th dose of LC₅₀) activity, vitellogenin production in muscle and hepatic- and reno-somatic indices were increased compared to control. With all the dose levels tested, testicular-somatic index (testis size) was reduced (P < 0.01) and histo-architectural changes in testicular and liver tissue were found even in group given 1/3rd dose of LC₅₀.     

Behavioral effects of acute exposure to the insecticide fipronil

The effects of fipronil (Frontline® Top Spot) were investigated in 40 days old rats utilizing open field (OF), hole-board (HB) and elevated plus-maze (EPM) apparatus. Rats (N = 15) received topical application of fipronil (70, 140 and 280 mg/kg) in the neck region and behavior was tested 3 h after administration. Animals treated with corn oil (vehicle) were used as controls. In the OF test animals treated with fipronil at 140 mg/kg showed increased rearing, whereas animals exposed to 280 mg/kg showed increased freezing, grooming, and rearing. In the HB test fipronil at 280 mg/kg increased head-dip and head-dipping behaviors. In the EPM test the only observed effect was increased number of entries in both open and closed EPM arms in animals treated with 280 mg/kg. In conclusion, dermal exposure to fipronil causes effects related to emotionality, fear, and exploratory activity; results add strength to the growing concern that pirazole insecticides can be neurotoxic to humans.     

Protective roles of vitamin E (α-tocopherol), selenium and vitamin E plus selenium in organophosphate toxicity in vivo: A comparative study

In the present study, we investigated the possible protective role of vitamin E, selenium (Se) and vitamin E plus Se in fenthion-induced organophosphates (OP) toxicity in rats. Serum concentrations of ascorbic acid, retinol, β-carotene, ceruloplasmin, nitrite and nitrate as well as levels of malondialdehyde (MDA) and reduced glutathion (GSH) in whole blood and in some tissues such as brain, heart, jejunum, kidney, liver, lung, muscle and pancreas were measured in sham, control, vitamin E, Se and vitamin E + Se groups. Compare to the sham group, the MDA (p < 0.001) and GSH (p < 0.01) levels in whole blood and some in tissues were significantly higher in the control animals. Ceruloplasmin levels of the control (p < 0.05), vitamin E (p < 0.05) and vitamin E + Se (p < 0.01), groups were higher than the sham group. Ascorbic acid, retinol, β-carotene as well as nitrite and nitrate levels in the control group were significantly lower than sham, vitamin E, Se and vitamin E + Se groups. We concluded that fenthion toxicity-induced lipid peroxidation and generation of free radicals in whole blood and tissues. Additionally, the antioxidants we tested did show a significant protective effect against OP-induced tissue and blood injury at the biochemical level.     

Cellular and biochemical effects induced by atrazine on blood of male Japanese quail (Coturnix japonica)

Atrazine a potent endocrine disruptor herbicide is broadly used to control rapidly growing unwanted weeds in various cereals crops which induce adverse effects both in mammalian and avian species. In present study 96 mature male Japanese quail (Coturnix japonica) were procured and randomly kept in eight groups (A to H) each having 12 birds. Atrazine was administered orally at 0, 10, 25, 50, 100, 250 and 500 mg/kg body weight to all experimental groups. The mitomycin C at 2 mg/kg body weight was given to the birds of group B which served as a positive control. From each group 4 birds were randomly selected and harvested at day 15, 30 and 45. A significant (P < 0.05) decrease in serum total protein, serum albumin and serum testosterone values were recorded at day 45 in all treated groups. A significant increase in serum ALT and AST concentration was also recorded. Moreover, morphological alterations in nucleus of erythrocytes were also observed including blebbed nuclei, notched nuclei, lobed nuclei, vacuolated cells, binucleated cell, and cell with pear shaped and micronucleus. Overall, our results show that atrazine at higher doses induces significant serum biochemical alterations and changes in nucleus of erythrocytes.     

Expression of esterase gene in yeast for organophosphates biodegradation

Organophosphates are esters of phosphoric acid and can be hydrolyzed and detoxified by carboxylesterase and phosphotriesterase. In this work esterase enzyme (Est5S) was expressed in yeast to demonstrate the organophosphorus hydrolytic activity from a metagenomic library of cow rumen bacteria. The esterase gene (est5S) is 1098 bp in length, encoding a protein of 366 amino acid residues with a molecular weight of 40 kDa. Est5S enzyme was successfully produced by Pichia pastoris at a high expression level of approximately 4.0 g L⁻¹. With p-nitrophenol butyrate as the substrate, the optimal temperature and pH for enzyme activity were determined to be 40 °C and pH 7.0, respectively. The esterase enzyme was tested for degradation of chlorpyrifos (CP). TLC results obtained inferred that CP could be degraded by esterase enzyme (Est5S) and HPLC results revealed that CP could be efficiently degraded up to 100 ppm. Cadusafos (CS), coumaphos (CM), diazinon (DZ) dyfonate (DF), ethoprophos (EP), fenamiphos (FM), methylparathion (MPT), and parathion (PT) were also degraded up to 68, 60, 80, 40, 45, 60, 95, and 100%, respectively, when used as a substrate with Est5S protein. The results highlight the potential use of this enzyme in the cleanup of contaminated insecticides.     

Cytogenetic effects of commercially formulated atrazine on the somatic cells of Allium cepa and Vicia faba

In the present study cytogenetic effects of atrazine herbicide, were examined on the root meristem cells of Allium cepa and Vicia faba. Test concentrations were chosen by calculating EC₅₀ values of formulated atrazine against both the test systems which determined to be 30 mg l⁻¹ for A. cepa and 35 mg l⁻¹ for V. faba, respectively. For cytogenetic effects root meristem cells of A. cepa were exposed to 15, 30 or 60 mg l⁻¹ whereas V. faba to 17.5, 35 or 70 mg l⁻¹ for 4 or 24 h. Roots exposed for 4 or 24 h, after sampling, were left in water for 24 h recovery and sampled at 24 h post-exposure. A set of onion bulbs or seedlings of V. faba exposed to DMSO (0.3%) was run parallel for negative control. Treatment of atrazine significantly and dose-dependently inhibited the mitotic index (MI) and induced micronucleus formation (MN) chromosome aberrations (CA) and mitotic aberrations (MA) in both the test systems at 4 or 24 h. Root meristem cells examined at 24 h post-exposure also revealed significant (p < 0.001) frequencies of MN, CA or MA despite considerable decline. Chromosome breaks and fragments were found to be major CA whereas C-metaphase, chromosome bridges and laggards were prevalent MA. Results of our study, indicate that atrazine may produce genotoxic effects in plants. Further, both the plant bioassays found to be sensitive indicators for the genotoxicity assessment as the outcome of majority of in vivo/in vitro mammalian tests are comparable.     

Changes in renal clearance and renal tubular function in albino mice under the influence of Dichlorvos

It is known that organophosphate pesticides and their metabolites are generally eliminated through urine and are likely to affect nephrons. Despite the widespread application of Dichlorvos only limited studies appear to have been done on its toxicity to kidney. Intraperitoneal administration of 400 μg/kg Dichlorvos in mice exhibited maximum reduction in total protein concentration of kidney after exposure to 120 h (52-fold decrease, t-test, P < 0.001). Variations in renal clearance and percent reabsorption of acid phosphatase, alkaline phosphatase and nonspecific esterase enzymes were significant at P < 0.01 and at P < 0.001 (2-way ANOVA), respectively. Maximum significant increase in renal contents of Na⁺ and Ca⁺⁺ was induced by 200 μg/kg dose after 120 and 240 h exposure (P < 0.001), while significantly highest retention of K⁺ and Cl⁻ ions was caused by 400 μg/kg dose after 24 and 72 h exposure (P < 0.01). Histopathological changes in glomeruli, PCTs, DCTs and CTs along with altered renal tubular function and renal clearance of enzymes and various ions indicate the development of acute renal disturbances under the influence of Dichlorvos.     

In vitro and in vivo effects of some pesticides on carbonic anhydrase enzyme from rainbow trout (Oncorhynchus mykiss) gills

Here we investigated the in vitro and in vivo effects of the pesticides, deltamethrin, diazinon, propoxur and cypermethrin, on the activity of rainbow trout (rt) gill carbonic anhydrase (CA). The enzyme was purified from rainbow trout gills using Sepharose 4B-aniline-sulfanilamide affinity chromatography method. The overall purification was approx. 214-fold. SDS-polyacrylamide gel electrophoresis showed a single band corresponding to a molecular weight of approx. 29 kDa. The four pesticides dose-dependently inhibited in vitro CA activity. IC₅₀ values for deltamethrin, diazinon, propoxur and cypermethrin were 0.137, 0.267, 0.420 and 0.460 μM, respectively. In vitro results showed that pesticides inhibit rtCA activity with rank order of deltamethrin > diazinon > propoxur > cypermethrin. Besides, in vivo studies of deltamethrin were performed on CA activity of rainbow trout gill. rtCA was significantly inhibited at three concentrations (0.25, 1.0 and 2.5 μg/L) at 24 and 48 h.