Influence of subacute and subchronic treatment of abcisic acid and gibberellic acid on serum marker enzymes and erythrocyte and tissue antioxidant defense systems and lipid peroxidation in rats

This study describes the subacute and subchronic effects of two plant growth regulators (PGRs) [abcisic acid (ABA) and gibberellic acid (GA₃)] on serum marker enzymes [aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine phosphokinase (CPK) and lactate dehydrogenase (LDH), γ-glutamil transpeptidase (GGT)], antioxidant defense systems [reduced glutathione (GSH), glutathione reductase (GR), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] and lipid peroxidation level (Malondialdehyde = MDA) in various tissues of rats. Rats (Sprague-Dawley albino) were exposed to 75 ppm (parts per million) of ABA and GA₃. Seventy-five parts per million of PGRs as drinking water was administered orally ad libitum for 25 and 50 days continuously. The PGRs treatments caused different effect on the serum marker enzymes, antioxidant defense systems and the content of MDA in comparison to those of control rats. Results show that ABA caused a significant decrease in serum LDH and CPK activity with both periods. Also, GA₃ significantly decreased serum AST, CPK, and LDH activity with subacute and decreased serum ALT, CPK, LDH, and GGT treated with subchronic periods. The lipid peroxidation end product MDA significantly increased in the erythrocyte, liver, brain, and muscle of rats treated with both the period of GA₃ without significantly change in the erythrocyte and muscle of rats treated with the subacute period of ABA. The GSH levels were significantly depleted in the erythrocyte and brain of rats treated with both the period of GA₃ without any change in the erythrocyte, liver, brain, and muscle of rats treated with both the period of ABA. Also GSH levels in the muscle significantly depleted with the subchronic period of GA₃. Antioxidant enzyme activities such as SOD significantly decreased in the erythrocyte, liver and brain tissues but increased in the muscle tissue of rats treated with both the periods of GA₃. Meanwhile, SOD significantly decreased in liver and brain, and increased in muscle of rats treated with both the period of ABA. While CAT significantly decreased in the all tissues of rats treated with both the period of GA₃, decreased in the liver and muscle of rats treated with both the periods of ABA too. On the other hand, the ancillary enzyme GPx and GR activity in the erythrocytes, liver, brain and muscle were either significantly depleted or not changed with two periods of PGRs. The drug metabolizing enzyme GST activity significantly decreased in the brain of rats treated with subacute period of PGRs but increased in the erythrocytes of rats treated with subacute period of GA₃. As a conclusion, ABA and GA₃ had significantly increased the activity of hepatic damage enzymes. Also the rats resisted to oxidative stress via antioxidant mechanism. However, the antioxidant mechanism could not prevent the increases in lipid peroxidation in rat’s tissues. These data, along with changes, suggest that PGRs produced substantial systemic organ toxicity in the erythrocyte, liver, brain, and muscle during the period of a 25-day subacute and 50-day subchronic exposure.     

Effects of indoleacetic acid and kinetin on lipid peroxidation and antioxidant defense in various tissues of rats

This study aims to investigate the effects of indoleacetic acid (IAA) and kinetin (Kn), which are plant growth regulators (PGRs), on antioxidant defense systems [reduced glutathione (GSH), glutathione-S-transferase (GST), catalase (CAT)], and lipid peroxidation level (malondialdehyde, MDA) various tissues of rats. Rats (Sprague-Dawley albino) were exposed to 100 ppm IAA and Kn. One hundred parts per million of PGRs was administered orally to rats ad libitum for 21 days continuously. The PGRs treatments caused different effects on the content of MDA and antioxidant defense system in comparison to those of control rats. According to the results, the subchronic treatments of IAA caused significant decrease in the GSH concentration and CAT activity in erythrocyte. Kn decreased GSH concentration in erythrocyte too. While the MDA concentration in brain was increased significantly by IAA and Kn, Kn decreased significantly brain CAT and GST activity. The liver GST activity was decreased by IAA and Kn. But, liver CAT activity was increased by IAA. On the other hand, while IAA treatment caused a significant decrease kidney GST activity, Kn caused a significant decrease both kidney GST and CAT activity. Also, while heart CAT activity was decreased by IAA, heart GST activity was decreased by both IAA and Kn. Moreover, MDA concentration in heart was increased by Kn treatment. It was concluded that IAA might effect MDA and antioxidant defense on the animals at subchronic treatment.     

Exposure to streptomycin alters oxidative and antioxidative response in larval midgut tissues of Galleria mellonella

Although antibiotics have different molecular modes of actions, increasing evidence for their secondary effects suggests that they disturb cellular homeostasis by generating free radical intermediates that trigger lipid peroxidation, which leads to oxidative stress. Streptomycin is an antibiotic insecticide used to control pest insects and microbial diseases of agricultural crops. We investigated the biochemical basis for pro-oxidative effects of streptomycin in the midgut tissues of greater wax moth, Galleria mellonella (L.) seventh-instar larvae by measuring content of the oxidative stress indicator, malondialdehyde (MDA), and antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) and glutathione peroxidase (GPx)] and transaminases [alanine aminotransferase (ALT), aspartate aminotransferase (AST)] activities. The insects were reared from first-instar larvae on artificial diets containing 0.001, 0.01, 0.1 or 1.0 g streptomycin per 100 g of diets. The supplementation of streptomycin at high concentrations to the diets caused oxidative stress as evidenced by the elevation of MDA content, SOD and GPx activities, accompanied by the concurrent depletion of CAT and GST activities. The streptomycin-induced oxidative stress was also accompanied by decreases of transaminases activities in midgut tissues. We found a significant negative correlation of MDA contents with GST activities in the larval midgut tissues. These results suggest that exposure to dietary streptomycin resulted in oxidative stress which could impact midgut digestive physiology at the expense of impairment of antioxidant and transaminases enzymes in G. mellonella larvae.     

Dimethoate induced biochemical perturbations in rat pancreas and its attenuation by cashew nut skin extract

The significant antiradical activity of cashew skin extract was previously described. In this investigation, the extent of protection offered by cashew nut skin extract (CSE) against the damage induced in rat pancreas by sub chronic doses dimethoate (DM), an organophosphorous pesticide was studied. Rats were supplemented with CSE at 20 mg/kg b.w./d after a daily dose of DM at 40 mg/kg/d b.w. for 2 months. Weekly random blood glucose, oral glucose tolerance test (OGTT); pancreatic damage markers like amylase and lipase; oxidative damage markers such as reactive oxygen species generated, extent of lipid peroxidation, host antioxidant defenses like reduced glutathione (GSH); GSH-dependent enzyme activities viz., glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR); free radical scavenger enzymes viz., catalase and superoxide dismutase (SOD); xenobiotic metabolizing enzymes like DT-diaphorase and NADPH-diaphorase were measured in the four different groups namely (1) control, (2) DM treated, (3) CSE supplemented, (4) CSE supplements following DM treatment. Random blood glucose levels increased significantly on exposure to DM compared to that in control rats (119 ± 5 mg/dl vs. 92 ± 4 mg/dl), while the blood glucose levels in CSE supplemented rats were comparable to that of controls. DM treated rats exhibited impaired glucose tolerance at the end of two months as indicated by OGTT, while DM treated rats with CSE supplements showed normal glucose tolerance. Pancreatic specific marker enzymes like amylase and lipase in serum were restored to normalcy in rats supplemented with CSE following treatment with DM which otherwise was increased in the DM treated rats. Distinctly lower levels of GSH, increased levels of ROS, higher extent of lipid peroxidation, along with alterations in antioxidant enzymes and increase in xenobiotic metabolizing enzymes were evident in pancreas of DM treated rats. However, CSE supplement ameliorated the biochemical alterations in the pancreatic milieu in DM treated rats. Treatment with CSE significantly protected rat pancreas from injury, thus ameliorating and restoring tissue antioxidant status and also conferring normal glucose tolerance. The active components present in cashew skin extract can perhaps be effective in reducing the extent of pancreatic injury and in overcoming tissue damage caused by exposure to dimethoate.     

Modulation of ethion-induced hepatotoxicity and oxidative stress by vitamin E supplementation in male Wistar rats

Organophosphorus insecticides (OPIs) may induce oxidative stress leading to generation of free radicals and alteration in antioxidant system of animals. Many studies reported that enzymatic and non-enzymatic antioxidant may play protective role against OPIs induced toxicity in human and rats. The aim of present study was to investigate the possible protective role of vitamin E on ethion-induced hepatotoxicity in rats using qualitative, quantitative and biochemical approaches. Adult male albino rats of Wistar strain were randomly divided into four groups; each group consists of six animals. Animals were treated for a period of 28 days. Group I (control group received corn oil); Group II [ethion treated (2.7 mg/kg bw/day)]; Group III (vitamin E treated (50 mg/kg of bw/day)]; Group IV (ethion + vitamin E treated). Animals were sacrificed after 7, 14, 21 and 28 days by decapitation and liver tissue was used for the measurement of proteins, lipid peroxidation (LPO), reduced glutathione (GSH) content and activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) glutathione reductase (GR) and glutathione-S-transferase (GST). Erythrocytes were analyzed for acetyl cholinesterase activity. The result of this study shows that in vivo administration of ethion caused a significant induction of oxidative damage in liver tissue as evidenced by increased level of LPO and decreased GSH content. Ethion toxicity also led to a significant increase in the activities of SOD, CAT, GPx and GST in liver tissue. In addition, decrease in GR activity was observed in ethion administered rats compared to control. Histopathological findings revealed that exposure to ethion caused damage in liver tissue. However, simultaneous supplementation with vitamin E restored these parameters partially. In conclusion, the results of the current study revealed that ethion-induced toxicity caused lipid peroxidation, alterations in the antioxidant enzymes and histopathological changes in liver. Supplementation of vitamin E exhibited protective effect by inhibiting ethion-induced toxicity in liver and erythrocytes.     

Effects of dimethoate (O,O-dimethyl S-methyl carbamoyl methyl phosphorodithioate) and Ethanol in antioxidant status of liver and kidney of experimental mice

Organophosphorus insecticides and ethanol individually cause free radical production induced by oxidative stress and alter the antioxidants and scavengers of free radicals. The present study indicates the effect caused by dimethoate in combination with ethanol on antioxidant status in mice. Daily, dimethoate at a dose of 18 mg/kg body weight and ethanol at 1 g/kg body weight were orally administered concurrently in a subacute study for 14 days. After the experimental period, the liver and kidney homogenates were analysed for various antioxidant enzymes. The results compared with dimethoate alone treated control indicated an increase in hepatic cytochrome P450 and lipid peroxidation. Decrease in superoxide dismutase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase, and glutathione in liver was observed. In kidney, decrease in CAT, SOD, GR, GST, and GSH was observed. Acetyl cholinesterase activity of RBC was increased. No significant change was observed in catalase in liver and glutathione peroxidase in kidney. The results of the study allow us to hypothesize that dimethoate along with ethanol disturbs the antioxidant status.     

Oxidative damage, biochemical and histopathological alterations in rats exposed to chlorpyrifos and the antioxidant role of zinc

The protective effects of zinc on liver and kidney injury induced by chlorpyrifos (CPF) were investigated in rats. Male and female rats were orally administered CPF at a dose of 6.75 mg kg⁻¹ body weight for 28 consecutive days. An additional CPF group received zinc (227 mg l⁻¹) in drinking water throughout the experimental duration. Two groups more served as controls. Administration of CPF resulted in a significant increase in serum lipid peroxidation (LPO) level, while induced significant decreases in the activities of plasma superoxide dismutase (SOD), glutathione-S-transferase (GST) and serum acetylcholinesterase (AChE) either in male or female rats. Similarly, a significant increase in the levels of various serum marker enzymes [e.g. aminotransferases (AST and ALT), lactate dehydrogenase (LDH) and gamma glutamyl transferase (GGT)] and increase the level of total protein, uric acid and creatinine. In contrast, co-administration of zinc to CPF-treated animals restored most of these biochemical parameters to within normal levels. In case of AChE, supplementation of zinc showed little alteration in the activity of this enzyme especially in male rats treated with CPF. CPF caused histopathological change in liver and kidneys of male and female rats. However, zinc administration to CPF-treated animals resulted in overall improvement in liver and kidneys damage, emphasizing its antioxidant role. In light of the available data, it can deduce that CPF-induced lipid peroxidation, oxidative stress, liver and kidneys damage in male and female rats, and conjunction supplementation of zinc has resulted in pronounced ameliorating effect.     

Oxidative stress, steroid hormone concentrations and acetylcholinesterase activity in Oreochromis niloticus exposed to chlorpyrifos

We investigated the endocrine disrupting effects of chlorpyrifos-ethyl which is suspected to be originated from oxidative stress. Initially, the 96 h LC₅₀ values of chlorpyrifos in juvenile and adult of Oreochromis niloticus were determined to be 98.67 μg/L and 154.01 μg/L, respectively. Sub-lethal concentrations of chlorpyrifos-ethyl (5 ppb, 10 ppb, 15 ppb) were administrated to adult fish for 15 and 30 days. Fish were then left to depurate for 15 days in pesticide-free water. Gonadal somatic indices, serum sex steroids as indicators of reproductive function and cortisol level as indicator of stress condition were measured to observe the endocrine disruption effects of chlorpyrifos-ethyl. Gonadal glutathione S-transferase and antioxidant enzyme activities and lipid peroxidation as indicators of oxidative stress were also measured. Acetylcholinesterase activity was measured as a marker of chlorpyrifos toxicity. Results showed that serum estradiol, testosteron and cortisol levels in fish exposed to chlorpyrifos were lower than those of the control fish while gonad somatic indices did not change during the experiments. After 30 days, chlorpyrifos exposure decreased GST activity, and increased SOD enzyme activity by up to 215-446% compared with the control, suggesting there was a oxidative stress. No statistically significant differences between GPx and CAT specific activities, protein contents and lipid peroxidation were determined between control and treatment groups in all exposure concentrations and periods. Acetylcholinesterase activity decreased (45.83-77.28%) in gonad tissues. After recovery serum estradiol and testosteron levels were similar to those of the control levels. An increase in the GST and SOD enzyme activities were determined. Cortisol level and AChE activity in all exposure groups decreased after the depuration period, and fish were unable to overcome the stress of chlorpyrifos. Thus, this study revealed that after chlorpyrifos treatments there exists a protective function of antioxidant enzymes against lipid peroxidation in gonad tissue of O. niloticus. There also exist lower testosteron and estradiol levels in exposed fish than those of the control fish without any alterations in oxidative stress, which is attributed to the capability of chlorpyrifos to impair steroid hormone levels.     

Effect of diethyl phthalate on rat testicular antioxidant system: A dose-dependent toxicity study

The experiment was designed to study toxic effects of diethyl phthalate (DEP) on testicular lipid peroxidation and testicular antioxidants in male Wistar rats for long-term exposure periods at varying concentrations. Healthy male rats were randomly assigned to five groups of six each. Group I male rats were fed on normal diet and water. Group II male rats were maintained on normal diet mixed with corn oil as oil control. Group III, IV and V rats were given diethyl phthalate (DEP) dissolved in minimal quantity of corn oil mixed with the diet at 10, 25 and 50 mg/kg of the diet/day, respectively, for 150 days. Body weight, testis weights, epididymis weight and the serum testosterone and androstenedione levels showed a significant decrease in the three treated groups. Testicular lipid peroxidation showed a significant dose-dependent increase, while testicular antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) were significantly decreased. These results confirm that, continuous administration of DEP at various concentrations on a long-term basis induces increased levels of lipid peroxidation leading to dose-dependent reduction in the testicular antioxidant defense system. Increased free radical production at various doses of DEP would result in impairment of the defense system leading to an enhanced dose-dependent reproductive toxic effect.     

Acute effects of methyl parathion and diazinon as inducers for oxidative stress on certain biomarkers in various tissues of rainbowtrout (Oncorhynchus mykiss)

Present study aimed mainly to assess oxidative stress pesticides such as methyl parathion (MP) and diazinon, which are widely used insecticides and contaminate aquatic ecosystems, on certain biomarkers in various tissues of rainbowtrout (Oncorhynchcus mykiss). Biomarkers selected for stress monitoring were malondialdehyde (MDA) and antioxidant defense system (ADS) mainly reduced glutathione (GSH), glutathione reductase (GR), peroxidase (GSH-PX), transferase (GST) and superoxidedismutase (SOD) activities in the liver, gills and muscle of fishes exposed to 0.5 and 1 ppm dosages of MP and diazinon for 24, 48 and 72 h. According to these results, after the administrations of MP and diazinon promote MDA content in some of the tissues of fishes treated with both dosages of MP and diazinon. With regard to the ADS, GSH-Px, GST, SOD, GR activities and GSH levels fluctuated after 24, 48 and 72 h in all the treatment groups compared with controls. Collective results demonstrated that exposure of fish to pesticides induced an increase in MDA joined with fluctuated ADS. This may reflect the potential role of these parameters as useful biomarkers for assessment of water pollution.     

Effects of dichlorvos on lipid peroxidation in mice on subacute and subchronic periods

In this study, the effects of dichlorvos to lipid peroxidation were investigated at subacute and subchronic periods. Dichlorvos was given with drinking water to Swiss Albino male mice in three dosage levels as 10, 20, and 40 mg/kg b.w. Lipid peroxidation was evaluated by determining the malondialdehyde (MDA) levels in plasma, determining the superoxide dismutase and catalase activities in erythrocytes. The analysis of these enzymes was done in blood samples collected from mice on the days 15 and 45. The results showed that MDA levels increased in dichlorvos treated groups. Actually MDA levels in control and dichlorvos treated groups were determined (as nmol/ml) 10.49, 13.83, 14.30, and 14.50, respectively, at subacute period; 7.77, 8.15, 10.88, and 12.33, respectively, at subchronic period. Catalase activity in erythrocytes decreased at subacute and subchronic periods in dichlorvos treated groups. At subacute period CAT activities were determined (as k/mg Hb) in control and dichlorvos treated groups, 563.45, 532.11, 524.76, and 497.08, respectively; 660.53, 588.84, 525.85, and 512.01, respectively, at subchronic period. When subacute and subchronic periods were compared with each other; it was shown that SOD and CAT activities increased at subchronic period.     

Antioxidant and immune potential marker enzymes assessment in the various tissues of rats exposed to indoleacetic acid and kinetin: A drinking water study

In the present study, the influence of two different PGRs, indoleacetic acid (IAA) and kinetin (Kn) on immune potential enzymes, adenosine deaminase (ADA) and myeloperoxidase (MPO), and antioxidant defense enzymes such as glutathione peroxidase (GPx), glutathione reductase (GR), and superoxide dismutase (SOD) in various tissues of rats were investigated during the treatment as a drinking water model. 100 ppm of IAA and Kn as drinking water were administered orally to rats (Sprague-Dawley albino) ad libitum for 21 days continuously. The PGRs treatments caused different effects on the immune potential and antioxidant defense enzymes of experimented rats compared to controls. Results show that IAA caused a significant decrease in GR activity in the lungs and liver and an increase in the spleen. Also, IAA caused a significant decline in GPx activity in the lungs and an increase in the heart. SOD was significantly reduced in the heart, while increased in the lungs. Furthermore, IAA caused a significant decrease in ADA activity in the heart and blood whereas an increase in the kidney and spleen. MPO activity was also significantly increased in the heart by IAA treatment. The activity of enzymes were also seriously affected by Kn; GR activity decreased in the lungs, brain, and blood while GPx activity decreased in the spleen, brain, and heart. ADA activity was also significantly reduced in the blood whereas MPO activity rose in the spleen. In addition, SOD activity lowered in all tissues except for lungs where a significant increment was determined. As a conclusion, the results indicate that PGRs might affect on antioxidant and immune potential enzymes. These data, along with the determined changes suggest that PGRs produced substantial systemic organ toxicity in the erythrocyte, liver, brain, heart, lungs, spleen, and kidney during the period of a 21-day subacute exposure.     

Antioxidant role of propolis extract against oxidative damage of testicular tissue induced by insecticide chlorpyrifos in rats

Pesticides induce oxidative stress leading to generate free radicals and alternate the antioxidant or oxygen free radical scavenging enzyme system. This study was conducted to investigate the oral toxicity of chlorpyrifos toward male rat and the oxidative stress of the sub-lethal dose (9 mg/kg; 1/25 LD₅₀) on the lipid peroxidation level (LPO), reduced glutathione content (GSH) and antioxidant enzymes; catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities of testicular tissue. Also, the protective effects of propolis extract (50 mg/kg b.w.) alone or in combination with chlorpyrifos were investigated. The oral administration of chlorpyrifos significantly caused elevation in LPO level by 1.79-fold as compared to control. The activities of antioxidant enzymes including CAT, SOD, GPx and GST were decreased significantly (23.66%, 27.75%, 29.13% and 11.52%) as well as the level of GSH decreased by 21.97% in testicular tissue as compared to control animals. Co-administration of propolis extract with chlorpyrifos or alone in male rats decreased LPO level, normalized CAT, SOD GPx and GST activities, while GSH content was increased in testicular tissue. We conclude that propolis extract significantly reduces chlorpyrifos-induced oxidative stress in rat testis and the protective effect of the pre-treatment with propolis extract as attenuating agent could be due to its antioxidant properties.     

A study on low dose cypermethrin induced histopathology, lipid peroxidation and marker enzyme changes in male rat

The short term effect of low dose synthetic pyrethroid and insecticide α-cypermethrin was investigated in selected tissues of male albino Wistar strain rats. Cellular antioxidant activities, specific enzyme markers and tissue histopathology were studied using this compound at 5, 10, 25 and 50 mM at given time points during independent experiments. α-Cypermethrin was administered intradermally. Selective tissue responses were determined 6 h post administration employing control and experimental animals using established methods. Different doses of α-cypermethrin increased the malondialdehyde (MDA) content in the brain, heart, liver, kidney and testis of the male rats. Alanine transaminase (ALT), alkaline phosphatase (ALP) and gamma glutamyl transferase (GGT) enzyme activity levels were altered in these tissues and in the serum. Cytotoxic effects produced by α-cypermethrin were reflected in histopathology sections of the treated tissues. α-Cypermethrin decreased the cellular antioxidant activity, altered marker enzyme activity and effected histopathological changes in the treated animal tissues.     

Toxic effects of novel organophosphorus insecticide (RPR-V) on certain biochemical parameters of euryhaline fish, Oreochromis mossambicus

The euryhaline fish, Oreochromis mossambicus was exposed to sub-lethal concentration (0.017 mg L⁻¹) of a novel phosphorothionate, 2-butenoic acid-3-(diethoxy phosphinothionyl) ethyl ester (RPR-V) for 30 days and allowed to recover for 7 days. Important biomarker enzymes were assayed in plasma, brain, gill, liver, kidney, and muscle during exposure tenures of day-3, -7, -15, -30, and also at 7 days (withdrawal) after stopping treatment. Acetylcholinesterase (AChE) activities of brain, gill, and muscle were strongly inhibited by 67, 75, and 66%, respectively, on day-30. Exposure (time) dependent increases in alanine aminotransferase (ALAT), and aspartate aminotransferase (ASAT), acid phosphatase (AcP), and alkaline phosphatase (AkP), activities in plasma and kidney; AcP and AkP activities in gill were noticed. However, significant decrease in ALAT, ASAT, AcP, and AkP activities in liver was observed. The depletion of glycogen was observed in liver, brain, and gill tissues, an indication of typical stress related response of the fish with pesticide. A significant increase in lactate dehydrogenase (LDH) activity in gill and brain was observed and decreased in liver and muscle, indicating tissue damage and muscular harm. Depletion of glutathione (GSH) was observed in the above tissues, there by enhancing the lipid peroxidation resulting in cell damage. The induction in hepatic glutathione-S-transferase (GST) levels indicates the protection against the toxicity of xenobiotic-induced lipid peroxidation. There was a significant recovery in all the above biochemical parameters, in all the tissues of fish after a recovery period of 7 days. These results revealed that RPR-V affects the intermediary metabolism of O. mossambicus and the increase of biomarker enzymes in plasma, might be due to the necrosis of liver.     

Biochemical effects of acute phoxim administration on antioxidant system and acetylcholinesterase in Oxya chinensis (Thunberg) (Orthoptera: Acrididae)

The study was undertaken to evaluate the effects of different concentrations of phoxim on acetylcholinesterase (AChE) and esterase (EST) activities, and antioxidant system after topical application to Oxya chinensis. The results showed that phoxim inhibited AChE activity, and did not cause significant changes in the EST activity and the levels of malondialdehyde (MDA) and reduced glutathione (GSH). After phoxim administration, superoxide (SOD) and catalase (CAT) activities showed a biphasic response with an initial increase followed by a decline in their activities. Glutathione reductase (GR) and glutathione peroxidase (GPx) activities were inhibited in comparison with the control. Glutathione S-transferase (GST) activity showed irregular changes. Its activity increased significantly at the concentrations of 0.06 and 0.12 μg/μL and decreased at the concentrations of 0.09 and 0.24 μg/μL compared with the control. Changes in SOD, CAT, GST, GPx, and GR activities indicated that phoxim caused oxidative damage in O. chinensis. However, no significant changes in MDA content suggested that these enzymes played important roles in scavenging the oxidative free radicals induced by phoxim in O. chinensis. The formation of oxygen free radicals might be a factor in the toxicity of phoxim.     

Ameliorative effect of lycopene on antioxidant status in Cyprinus carpio during pyrethroid deltamethrin exposure

The aim of the present study was to investigate the ameliorative properties of lycopene against the toxic effects of deltamethrin (DM) by examining oxidative damage markers such as lipid peroxidation and the antioxidant defense system components in carp (Cyprinus carpio). The fish were divided into seven groups of 15 fish each and received the following treatments: Group 1, no treatment; Group 2, orally administered corn oil; Group 3, oral lycopene (10 mg/kg body weight); Group 4, exposure to 0.018 μg/L DM; Group 5, exposure to 0.018 μg/L DM plus oral administration of 10 mg/kg lycopene; Group 6, exposure to 0.036 μg/L DM; and Group 7, exposure to 0.036 μg/L DM plus oral administration of 10 mg/kg lycopene. Treatment was continued for 14 days, and at the end of this period, blood and tissue (liver, kidney, and gill) samples were collected. Levels of malondialdehyde (MDA) and reduced glutathione (GSH) as well as superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities were determined in blood and tissues for measurement of oxidant-antioxidant status. A significant elevation in the level of MDA, as an index of lipid peroxidation, and reductions in antioxidant enzyme activities (SOD, CAT, and GSH-Px) and low molecular weight antioxidant (GSH) levels were observed in DM-exposed fish. Treatment with lycopene attenuated the DM-induced oxidative stress by significantly decreasing the levels of MDA. In addition, lycopene significantly increased the SOD, CAT, and GSH-Px activities and the level of GSH. The present results suggest that administration of lycopene might alleviate DM-induced oxidative stress.     

Lipid peroxidation and oxidative stress in rat erythrocytes induced by chlorpyrifos and the protective effect of zinc

Male and female rats were orally administered chlorpyrifos at a dose of 6.75 mg kg⁻¹ body weight for 28 consecutive days. An additional chlorpyrifos group received zinc (227 mg l⁻¹) in drinking water throughout the experimental duration. Two groups more served as controls; one received water only and the other received zinc in drinking water. Administration of chlorpyrifos resulted in a significant increase in lipid peroxidation (LPO) level and significant decrease in the activities of superoxide dismutase (SOD), glutathione-s-transferase (GST), catalase (CAT) and acetylcholinesterase (AChE) in erythrocytes of male and female rats. In contrast, zinc-chlorpyrifos treatment showed insignificant differences (p ? 0.05-0.01), compared to control results, regarding LPO, SOD, GST and CAT. In case of AChE, supplementation of zinc showed little alteration in the activity of this enzyme in the rats treated with chlorpyrifos. It can deduce that chlorpyrifos induced oxidative stress and lipid peroxidation in erythrocytes of male and female rats. The overall results reveal the pronounced ameliorating effect of zinc in chlorpyrifos-intoxicated rats and variation in the response of male and female animals regarding alteration in the level of some biochemical parameters and LPO.     

Allelochemical ethyl 2-methyl acetoacetate (EMA) induces oxidative damage and antioxidant responses in Phaeodactylum tricornutum

Ethyl 2-methyl acetoacetate (EMA) is a novel allelochemical exhibiting inhibitory effects on the growth of marine unicellular alga Phaeodactylum tricornutum (P. tricornutum). Oxidative damage and antioxidant responses in P. tricornutum were investigated to elucidate the mechanism involved in EMA inhibition on algal growth. The increase in reactive oxygen species (ROS) levels and malondialdehyde (MDA) contents following exposure to EMA suggested that alga was suffered from oxidative stress and severely damaged. The decrease in cell activity and cellular inclusions suggested that cell growth was greatly inhibited. The activities of the antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxide (GSH-PX) and glutathione S-transferase (GST) increased with the exposure concentration and decreased with the prolongation of exposure time. Cellular ascorbic acid (AsA) and reduced glutathione (GSH) systems were also involved in resisting oxidative stress of EMA by altering the composition of AsA and GSH pools. EMA exposure increased the contents of AsA, GSH, dehydroascorbate (DAsA) and glutathione (GSSG). However, the regeneration rate of AsA/DAsA did not change obviously between treatments and the control, while that of GSH/GSSG decreased significantly under 14 mmol/L EMA exposure on the 3rd day. These results showed that EMA-induced oxidative damage might be responsible for EMA inhibition on P. tricornutum growth and cellular antioxidant enzymes and non-enzymatic antioxidants were improved to counteract the oxidative stress.     

Salicylic acid alleviates growth inhibition and oxidative stress caused by zucchini yellow mosaic virus infection in Cucurbita pepo leaves

The effects of zucchini yellow mosaic virus (ZYMV) infection and pretreatments with salicylic acid (SA) on biomass accumulation of pumpkin (Cucurbita pepo cv. Eskandarani) were investigated. The response of photosynthesis, transpiration and the activities of antioxidant enzymes in leaves was also considered. Significant reductions in growth parameters (i.e. leaf area, biomass and shoot height), photosynthesis and chlorophyll a and b content were detected in ZYMV-infected leaves in comparison to healthy controls. Antioxidant enzyme activities were increased up to 3-fold for peroxidase (POD), 2-fold for ascorbate peroxidase (APX) and catalase (CAT) activities and 1.3-fold for SOD activity by virus infection. ZYMV infection also caused increases in H₂O₂ and malondialdehyde (MDA) contents. These results suggest that ZYMV infection causes oxidative stress in pumpkin leaves leading to the development of epidemiological symptoms. Interestingly, spraying pumpkin leaves with SA led to recovery from the undesirable effects of ZYMV infection. Leaves treated with 100 μM SA three days before inoculation had the appearance of healthy leaves. No distinct disease symptoms were observed on the leaves treated with 100 μM SA followed by inoculation with ZYMV. In non-infected plants, SA application increased activities of POD and superoxide dismutase (SOD) and inhibited APX and CAT activities.In contrast, SA treatment followed by ZYMV inoculation stimulated SOD activity and inhibited activities of POD, APX and CAT. In addition, MDA displayed an inverse relation, indicating inhibition of lipid peroxidation in cells under SA treatment. It is suggested that the role of SA in inducing plant defense mechanisms against ZYMV infection might have occurred through the SA-antioxidant system. Such interference might occur through inhibition or activation of some antioxidant enzymes, reduction of lipid peroxidation and induction of H₂O₂ accumulation following SA application.