Ginger extract ameliorates phosphamidon induced hepatotoxicity.

Organophosphorus (OP) compounds commonly used as pesticides in agriculture cause serious health problems to living beings. The present study enumerates the ameliorating effect of ginger extract (GE) against phosphamidon (PHO, an organophosphorus insecticide) induced hepatotoxicity. GE was prepared from dried ginger and characterized for compound profile and antioxidant activity. Eight groups of albino rats (n = 6) were treated with 1/5th lethal dose of PHO for 5-20 days. Out of the treated 8 groups, 4 were simultaneously fed with GE (1 mg/kg body wt.) along with PHO. Alterations in the levels of hepatocellular oxidative stress (OS) markers in the treated groups indicated an enhanced generation of reactive oxygen species (ROS) and oxidative stress (OS). Upregulation of apoptotic markers, DNA fragmentation and appearance of apoptotic nuclei suggested induction of apoptosis in the liver cell that was found to be attenuated after GE treatment. Moreover, no toxicity and mortality was observed up to 100 mg/kg dose of GE for 30 days in the rat model studied. Thus, GE can be considered as an effective, economical and safe extract to circumvent PHO-induced hepatotoxicity.

Neurotoxic impact of organophosphate pesticide phosphomedon on the albino rat.

Organophosphate pesticide phosphomedon was exposed to albino rat at a concentration of 35 ppm in the time interval of 30, 45 and 60 days. During the exposure period neurobehavioral symptoms such as reduce food intake, weight loss, increase water intake, low defecation frequency, increase locomotion frequency at high dose were observed. Locomotion frequency were less initially but higher in increasing dose concentration. The result was also different in both the sexes. A decrease social interaction and increase force swimming with increasing dose concentration, which was not significant as comparison to control. A significant histopathological changes observed in three dose concentrations. In 30 days phosphomedon exposure the nuclear shape changes to oval, pear shaped along with fibrosis, lipidosis, 45 days exposure showed the increase number of nucleus, Chromatolysis, inflammatory nucleus, pyknosis. In 60 days test group histopathological picture showed the swelling of cell body, lipidosis, demylination, necrosis in brain cells. Over all result indicated that due to impact of O. P pesticide phosphomedon a severe histopathological changes occurs which was distinctly observed in neurobehavioural changes.

Effect of piracetam and vitamin E on phosphamidon-induced impairment of memory and oxidative stress in rats.

Organophosphate pesticides, such as phosphamidon (PHOS), have been shown to adversely affect memory and induce oxidative stress after both acute and chronic exposure. The present study was therefore designed to investigate the effects of piracetam (PIR) and vitamin E on PHOS-induced modulation of cognitive function and oxidative stress in rats. Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. Oxidative stress was assessed by examining the levels of malondialdehyde (MDA) and nonprotein thiols (NP-SH) in isolated homogenized whole brain samples. The results showed a significant reduction in SDL and a prolongation of TL in the PHOS (1.74 mg/kg/day per oral; p.o.)-treated group at weeks 6 and 8, as compared to the control group. Administration of PIR (600 mg/kg/day p.o.) or vitamin E (125 mg/kg/day p.o.) for 2 weeks antagonized the effect of PHOS on SDL as well as TL. PHOS per se produced a significant increase in brain MDA levels and a decrease in brain NP-SH levels, whereas administration of PIR (600 mg/kg/day p.o.) or vitamin E (125 mg/kg/day p.o.) attenuated these effects. Thus, the results of the study showed that both PIR and vitamin E attenuated the cognitive dysfunction and oxidative stress induced by PHOS in the rat brain.

Melatonin attenuates cognitive dysfunction and reduces neural oxidative stress induced by phosphamidon.

Melatonin is an important modulator of nervous system functioning and important neural antioxidant. Organophosphate pesticides like phosphamidon (PHOS) have been shown to adversely affect memory and induce oxidative stress on both acute and chronic exposure. This study was designed to explore the modulation of the effects of PHOS on cognitive function by melatonin (MEL). Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. Oxidative stress was assessed by examining the levels of malondialdehyde (MDA) and nonprotein thiols (NP-SH) in isolated homogenized whole brain samples. The results showed a significant reduction in SDL and prolongation of TL in the PHOS (1.74 mg/kg/day; p.o.)-treated group at weeks 6 and 8 as compared to the control group. Two-week treatment with MEL (5 mg/kg/day; i.p.) antagonized the effect of PHOS on SDL as well as TL. PHOS alone produced a significant increase in the brain MDA levels and decrease in the brain NP-SH levels. Treatment with MEL attenuated the effect of PHOS on oxidative stress. Together the results showed that MEL attenuated the cognitive dysfunction and decreased oxidative stress induced by PHOS in the brain.

Age-related differences in acute neurotoxicity produced by mevinphos, monocrotophos, dicrotophos, and phosphamidon.

Age-related differences in the acute neurotoxicity of cholinesterase (ChE)-inhibiting pesticides have been well-studied for a few organophosphates, but not for many others. In this study, we directly compared dose-responses using brain and red blood cell (RBC) ChE measurements, along with motor activity, for mevinphos, monocrotophos, dicrotophos, and phosphamidon. Long-Evans hooded male rats were tested as adults and at postnatal day (PND) 17; PND11 pups were also tested with dicrotophos only. All chemicals were administered via oral gavage and tests were conducted at times intended to span peak behavioral and ChE effects. All OPs tested produced a rapid onset and recovery from the behavioral effects. There were age-related differences in the inhibition of brain, but not necessarily RBC, ChE. Mevinphos was clearly more toxic, up to 4-fold, to the young rat. On the other hand, monocrotophos, dicrotophos, and phosphamidon were somewhat more toxic to the young rat, but the magnitude of the differences was < 2-fold lower. Motor activity was consistently decreased in adults for all chemicals tested; however, there was more variability with the pups and clear age-related differences were only observed for mevinphos. These data show that three of these four OPs were only moderately more toxic in young rats, and further support findings that age-related differences in pesticide toxicity are chemical-specific.

Effect of progesterone on phosphamidon-induced impairment of memory and oxidative stress in rats.

Progesterone (a neurosteroid) is an important modulator of the nervous system functioning. Organophosphorus pesticides like phosphamidon have been shown to adversely affect memory and induce oxidative stress on both acute and chronic exposure. The present study was therefore designed to investigate the effects of progesterone (PROG) on phosphamidon-induced modulation of cognitive function and oxidative stress in rats. Cognitive function was assessed using step-down latency (SDL) on a passive avoidance apparatus and transfer latency (TL) on an elevated plus maze. Oxidative stress was assessed by examining the levels of thiobarbituric acid reactive species (TBARS) and non-protein thiols (NP-SH) in isolated homogenized whole brain samples. The results showed a significant reduction in SDL and prolongation of TL in the phosphamidon (1.74 mg/kg/d; p.o.) treated group at weeks 6 and 8 as compared to the control group. Two weeks treatment with PROG (15 mg/kg/d; i.p.) antagonized the effect of phosphamidon on SDL as well as TL. Phosphamidon alone produced a significant increase in the brain TBARS levels and decrease in the brain NP-SH levels. Treatment with PROG (15 mg/kg/d; i.p.) attenuated the effect of phosphamidon on oxidative stress. Together, the results showed that progesterone attenuated the cognitive dysfunction and increased oxidative stress induced by phosphamidon in the brain.

Ameliorating effect of N-acetylcysteine and curcumin on pesticide-induced oxidative DNA damage in human peripheral blood mononuclear cells.

Endosulfan, malathion, and phosphamidon are widely used pesticides. Subchronic exposure to these contaminants commonly affects the central nervous system, immune, gastrointestinal, renal, and reproductive system. There effects have been attributed to increased oxidative stress. This study was conducted to examine the role of oxidative stress in genotoxicity following pesticide exposure using peripheral blood mononuclear cells (PBMC) in vitro. Further possible attenuation of genotoxicity was studied using N-acetylcysteine (NAC) and curcumin as known modulators of oxidative stress. Cultured mononuclear cells was isolated from peripheral blood of healthy volunteers, and exposed to varying concentrations of different pesticides: endosulfan, malathion, and phosphamidon for 6, 12, and 24 h. Lipid peroxidation was assessed by cellular malondialdehyde (MDA) level and DNA damage was quantified by measuring 8-hydroxy-2'-deoxyguanosine (8-OH-dG) using ELISA. Both MDA and 8-OH-dG were significantly increased in a dose-dependent manner following treatment with these pesticides. There was a significant decrease in MDA and 8-OH-dG levels in PBMC when co-treated with NAC or/and curcumin as compared to pesticide alone. These results indicate that pesticide-induced oxidative stress is probably responsible for the DNA damage, and NAC or curcumin attenuate this effect by counteracting the oxidative stress.

Assessment of phosphamidon-induced apoptosis in human peripheral blood mononuclear cells: protective effects of N-acetylcysteine and curcumin.

The molecular mechanism for noncholinergic toxicity of phosphamidon, an extensively used organophosphate pesticide, is still not clear. The aim of the present study is to find the possible molecular mechanism of this pesticide to induce apoptosis and the role of different drugs for attenuation of such effects. Human peripheral blood mononuclear cells (PBMC) were incubated with increasing concentrations of phosphamidon (0-20 µM) for 6-24 h. The MTT assay reveals that phosphamidon induces cytotoxicity in a dose-dependent manner. Cellular glutathione (GSH) is depleted in a dose-dependent manner from 55% to 70% at concentrations between 10 and 20 µM. The percentage of cells that bind to Annexin-V, which is a representative of cells either undergoing apoptosis or necrosis during 24 h incubation, increases in a dose-dependent manner. Above 5 µM, significant necrosis of cells was observed. DNA fragmentation assay revealed that at low concentration of phosphamidon (1 µM), no appreciable change in DNA fragmentation was seen; however, distinct fragmentation was observed beyond 2.5 µM. Phosphamidon was found to cause significant depletion of GSH, which correlates well with the percentage of cells undergoing apoptosis. An increasing trend in levels of cytochrome c was observed with increasing concentration of phosphamidon, indicating that the apoptotic effect of phosphamidon is mediated through cytochrome c release. Coadministration of the antioxidants N-acetylcysteine and curcumin attenuated phosphamidon-induced apoptosis. This further supports our hypothesis that oxidative stress, as indicated by GSH depletion, results in the induction of apoptosis by release of cytochrome c.

Effect of phosphamidon on convulsive behavior and biochemical parameters: modulation by progesterone and 4'-chlorodiazepam in rats.

Phosphamidon (PHOS) has been shown to affect nervous system adversely. The present study was designed to explore the modulation of the effects of PHOS on convulsions by neurosteroids, progesterone (PROG), and 4'-chlorodiazepam (4'-CD), in both acute and chronic seizure models. In acute study, seizures were induced by either pentylenetetrazole (PTZ) injection or maximal electroshock seizures, while in the chronic study, kindling was induced by injecting PTZ (30 mg/kg, s.c.) on alternate days three times in a week. Oxidative stress was assessed in the brain by measuring the levels of malondialdehyde (MDA), acetylcholinesterase (AChE), and non-protein thiol (NP-SH). PROG and 4'-CD were able to modulate the PHOS-induced convulsions in acute PTZ convulsions as well as in chronic kindling model. However, they failed to reverse the derangements in oxidative stress parameters of MDA and NP-SH produced by PHOS in kindled animals. PROG significantly increased the AChE activity in untreated rats, while PROG and 4'-CD reversed the AChE activity inhibition induced by PHOS. The study indicates a possible anticonvulsive mechanism of neurosteroids, since both PROG and 4'-CD reversed PHOS-induced inhibition of AChE activity. The neurosteroids seem to play a protective role in PHOS-induced convulsions besides their antioxidant property.

Determination of pesticides and toxic potency of rainwater samples in western Greece.

Rainwater samples from four municipalities located in Achaia Prefecture, Greece, were collected from March to September 2006. The toxic potency of pollutants present in 36 rainwater samples was tested using Daphnia pulex. The pesticide determination was conducted with GC-MS. Only phosphamidon was detected, which appeared in 52% and 13% of the rural and urban areas, respectively. The toxicity of rainwater was determined in 52% and 46.7% of the rural and urban area samples, respectively. Chemical analyses showed that in rural areas, the PO(4)(3-) ions had higher concentrations than in urban areas. On the other hand, the SO(4)(2-), NO(-)(3), and NO(-)(2) anions are more highly concentrated in urban areas. Correlation analysis proved that the toxicity of the rainwater samples is moderate, affected by the presence of the insecticide only in the rural areas. The results indicated that toxicity can be directly assessed via bioassays, even when unknown pollutants are present.

Attenuation of phosphamidon-induced oxidative stress and immune dysfunction in rats treated with N-acetylcysteine.

The effect of N-acetylcysteine, a thiolic antioxidant, on attenuation of phosphamidon-induced oxidative stress and immune dysfunction was evaluated in adult male Wistar rats weighing 200-250 g. Rats were divided into four groups, 8 animals/group, and treated with phosphamidon, N-acetylcysteine or the combination of both for 28 days. Oral administration of phosphamidon (1.74 mg/kg), an organophosphate insecticide, increased serum malondialdehyde (3.83 +/- 0.18 vs 2.91 +/- 0.24 nmol/mL; P < 0.05) and decreased erythrocyte superoxide dismutase (567.8 +/- 24.36 vs 749.16 +/- 102.61 U/gHb; P < 0.05), catalase activity (1.86 +/- 0.18 vs 2.43 +/- 0.08 U/gHb; P < 0.05) and whole blood glutathione levels (1.25 +/- 0.21 vs 2.28 +/- 0.08 mg/gHb; P < 0.05) showing phosphamidon-induced oxidative stress. Phosphamidon exposure markedly suppressed humoral immune response as assessed by antibody titer to ovalbumin (4.71 +/- 0.51 vs 8.00 +/- 0.12 -log(2); P < 0.05), and cell-mediated immune response as assessed by leukocyte migration inhibition (25.24 +/- 1.04 vs 70.8 +/- 1.09%; P < 0.05) and macrophage migration inhibition (20.38 +/- 0.99 vs 67.16 +/- 5.30%; P < 0.05) response. Phosphamidon exposure decreased IFN-small u, Cyrillic levels (40.7 +/- 3.21 vs 55.84 +/- 3.02 pg/mL; P < 0.05) suggesting a profound effect of phosphamidon on cell-mediated immune response. A phosphamidon-induced increase in TNF-alpha level (64.19 +/- 6.0 vs 23.16 +/- 4.0 pg/mL; P < 0.05) suggests a contributory role of immunocytes in oxidative stress. Co-administration of N-acetylcysteine (3.5 mmol/kg, orally) with phosphamidon attenuated the adverse effects of phosphamidon. These findings suggest that oral N-acetylcysteine treatment exerts protective effect and attenuates free radical injury and immune dysfunction caused by subchronic phosphamidon exposure.

Attenuation of phosphamidon-induced oxidative stress and immune dysfunction in rats treated with N-acetylcysteine

The effect of N-acetylcysteine, a thiolic antioxidant, on attenuation of phosphamidon-induced oxidative stress and immune dysfunction was evaluated in adult male Wistar rats weighing 200-250 g. Rats were divided into four groups, 8 animals/group, and treated with phosphamidon, N-acetylcysteine or the combination of both for 28 days. Oral administration of phosphamidon (1.74 mg/kg), an organophosphate insecticide, increased serum malondialdehyde (3.83 ± 0.18 vs 2.91 ± 0.24 nmol/mL; P < 0.05) and decreased erythrocyte superoxide dismutase (567.8 ± 24.36 vs 749.16 ± 102.61 U/gHb; P < 0.05), catalase activity (1.86 ± 0.18 vs 2.43 ± 0.08 U/gHb; P < 0.05) and whole blood glutathione levels (1.25 ± 0.21 vs 2.28 ± 0.08 mg/gHb; P < 0.05) showing phosphamidon-induced oxidative stress. Phosphamidon exposure markedly suppressed humoral immune response as assessed by antibody titer to ovalbumin (4.71 ± 0.51 vs 8.00 ± 0.12 -log2; P < 0.05), and cell-mediated immune response as assessed by leukocyte migration inhibition (25.24 ± 1.04 vs 70.8 ± 1.09%; P < 0.05) and macrophage migration inhibition (20.38 ± 0.99 vs 67.16 ± 5.30%; P < 0.05) response. Phosphamidon exposure decreased IFN-у levels (40.7 ± 3.21 vs 55.84 ± 3.02 pg/mL; P < 0.05) suggesting a profound effect of phosphamidon on cell-mediated immune response. A phosphamidon-induced increase in TNF-α level (64.19 ± 6.0 vs 23.16 ± 4.0 pg/mL; P < 0.05) suggests a contributory role of immunocytes in oxidative stress. Co-administration of N-acetylcysteine (3.5 mmol/kg, orally) with phosphamidon attenuated the adverse effects of phosphamidon. These findings suggest that oral N-acetylcysteine treatment exerts protective effect and attenuates free radical injury and immune dysfunction caused by subchronic phosphamidon exposure.

Protective effect induced by atropine, carbamates, and 2-pyridine aldoxime methoiodide Artemia salina larvae exposed to fonofos and phosphamidon.

The acute toxicity of fonofos and phosphamidon on three age classes of Artemia salina was evaluated. An increase in toxicity of these organophosphorous (OP) insecticides was found following longer development of A. salina. The effects of pretreatment with the nonselective muscarinic antagonist atropine, the two reversible acetylcholinesterease inhibitors physostigmine and pyridostigmine, and the cholinesterase-reactivating oxime 2-pyridine aldoxime methoiodide (2-PAM), as individual and combined pretreatments, on OP-induced lethality in 24 h Artemia were also investigated. The lethal action of both OP insecticides was prevented by pretreatment of 24 h Artemia with atropine and 2-PAM, while physostigmine proved ineffective against intoxication with both OP insecticides and pyridostigmine exhibited a low synergic effect. In both cases, the inhibitory effects of combinations of atropine (10(-5)M) plus 2-PAM were greater than those elicited by either drug alone, with the maximum protection afforded being 100%. Combined pretreatment of atropine (10(-5)M) plus physostigmine practically abolished the lethal effects induced by both insecticides. Pretreatment with 2-PAM (10(-6)M) plus physostigmine afforded maximal protection of 100% and 76% on the lethality induced by fonofos and phosphamidon, respectively. The data obtained suggest that the combination of atropine plus 2-PAM or physostigmine and the combined pretreatment of 2-PAM plus physostigmine are effective in the prevention of the lethal effects induced by fonofos and phosphamidon in A. salina larvae.

Immunotoxicity of phosphamidon following subchronic exposure in albino rats.

Effect of subchronic doses of phosphamidon exposure on humoral and cell mediated immune (CMI) responses were studied in male albino rats using SRBC, ovalbumin and KLH as antigens. Humoral immune responses were assessed by estimating antibody titre against antigen and splenic plaque forming cells (PFC) assay. CMI responses were studied by using leucocyte migration inhibition (LMI), macrophage migration inhibition (MMI) and delayed type hypersensitivity (DTH) response. Results obtained in the present study revealed marked suppression of humoral and CMI responses in a dose dependent pattern. Hence, suppression of immune responses by phosphamidon even at subchronic doses is clearly an important aspect for its safety evaluation.

Effect of phosphamidon on the testes of albino rats: a histological study.

The present study shows the qualitative and quantitative histological changes in testes of albino rats treated with two doses of phosphamidon 35 and 50 parts per million(ppm) for 1 month time period. Rats were treated by drinking water containing 35 ppm (low dose) and 50ppm (high dose) concentration of phosphamidon for 30 days. After 30 days, they were sacrificed, the testes were fixed in vivo and were taken out. The histological slides of these testes were prepared and were studied under light microscope. The decrease in the weight of testes and diameter of seminiferous tubules, increase in the interstitial space, the decrease in the numbers of germ cells and supporting cells, Cytoplasmic vacuolization of the germ cells, distortion of seminiferous tubules were the findings of present study. phosphamidon seems to be toxic on male reproductive system if exposed for prolong period. The awareness regarding the impact of phosphamidon should be given to farmer and they should be encouraged to practice biological means to control pests and herbs instead of these harmful chemical compounds.

Endocrine response of the freshwater teleost, Sarotherodon mossambicus (Peters) to dimecron exposure.

The endocrine response in a freshwater teleost, Sarotherodon mossambicus (Peters) under dimecron (an organophosphate pesticide) toxicity was investigated by estimating the serum levels of T3 (triiodothyronine), T4 (thyroxine), cortisol, prolactin and insulin in control and sub-lethal (0.001 ml l(-1)) dimecron-exposed fish for 1, 6, 12, 24h and 5 days. In control S. mossambicus, the serum levels of T3 ranged from 0.80+/-0.01 to 0.82+/-0.01 ng ml(-1); T4 from 2.20+/-0.01 to 2.25+/-0.01 microg dl(-1); cortisol from 8.30+/-0.03 to 8.34+/-0.01 microg dl(-1); prolactin from 1.50+/-0.01 to 1.54+/-0.01 microg ml(-1); insulin from 9.70+/-0.01 to 9.76+/-0.01 microU ml(-1) up to a maximum period of 5 days maintained in pollutant-free tap water. Exposure of fish to sub-lethal concentration of dimecron caused varying changes in the levels of serum hormones studied. Based on the results obtained, it was concluded that (i) the fish adaptively maintains a probable low metabolic rate, as indicated by the reduced levels of thyroid hormone (T3) as well as the glucocorticoid hormone (cortisol), which could be considered advantageous for the fish to indirectly reduce the toxic impact of the pesticide, (ii) the elevated levels of prolactin in the fish under pesticide stress is indicative of a possible hydromineral regulatory effect of the hormone (probably by influencing specific organs such as gills and kidney) under pesticide toxicity, (iii) the increased insulin level in the fish under pesticide stress is indicative of its role in favouring an adaptive tissue glycogenesis besides a possible increased lipogenesis to sequester the pesticide residue thereby reducing the toxic effect of the pesticide and (iv) the prolonged exposure of the fish (for 5 days) to sub-lethal dimecron appeared to exhibit a uniform recovery response in the different hormonal levels of the fish.

Influence of the organophosphorus insecticide phosphamidon on lentic water.

The inland freshwater resources are being increasingly subjected to heavy stress as a result of indiscriminate dumping of industrial wastes, domestic sewage and agricultural run-off causing deterioration of the water quality and adverse impact on aquatic biota. Pesticides drained to the aquatic environment are primarily of agricultural origin. Phosphamidon (widely used organophosphate pesticide in paddy field) significantly reduced dissolved oxygen (DO) at 1.8 mg/l exposure and reduced alkalinity at 0.9 and 1.8 mg/l. Hardness also reduced gradually but not significantly. Free carbondioxide was increased significantly at 1.8 mg/l of the insecticide compared to control. The insecticide had no influence on pH and temperature. There was maximum reduction of phytoplankton and zooplankton population at 1.8 mg/l of phosphamidon. Though gradual reduction of plankton community was also noticed at different lower concentrations of pesticides but in case of phytoplankton an abrupt reduction (about 50% of the control) was observed. The normal behaviour and feeding rate of air breathing teleost, Channa punctatus was also hampered. Therefore, phosphamidon even at low concentrations may create disorders in the aquatic ecosystem.

Effects of dimecron on developing chick embryo: malformations and other histopathological changes.

The effect of dimecron, an organophosphorus insecticide, on developmental alterations and histopathological damage was determined in the developing chick embryo. The insecticide was administered at two different doses (25 microg and 35 microg) into the egg yolk through a pore into the equatorial region at day 0 of incubation. Significant abnormalities in relation to organogenesis and overall retardation in growth were noted in the insecticide-treated embryos. Histopathological study of the treated whole embryo showed abnormal features in the formation of different vital organs. The liver and kidney were severely affected by the pesticide at both doses. Based upon these findings it may be concluded that dimecron does play a role in producing embryotoxicity at different stages of embryogenesis.

Effect of dimecron on the blood parameters of Heteropneustes fossilis.

The effects of an organophosphate insecticide. dimecron. has been studied on certain haematological parameters, viz., haemoglobin concentration, RBC number, haematocrit, O2 carrying capacity of blood, etc. of Heteropneustes fossilis following exposures to the LC50 for 24 h and 96 h and 1/10 and 1/50 parts of 96 h LC50 for 90 days. There was a significant decrease in the Hb%, RBC number, HCt% and O2 carrying capcity of blood. But, there was significant increase in the MCH and MCV values following both acute and chronic exposures. The results indicate possible induction of anaemia in the exposed fish.