Influence of subacute treatment of some plant growth regulators on serum marker enzymes and erythrocyte and tissue antioxidant defense and lipid peroxidation in rats

2,4-D Herbicide-Induced Hepatotoxicity: Unveiling Disrupted Liver Functions and Associated Biomarkers

2,4-dichlorophenoxyacetic acid (2,4-D) is a widely used herbicide worldwide and is frequently found in water samples. This knowledge has prompted studies on its effects on non-target organisms, revealing significant alterations to liver structure and function. In this review, we evaluated the literature on the hepatotoxicity of 2,4-D, focusing on morphological damages, toxicity biomarkers and affected liver functions. Searches were conducted on PubMed, Web of Science and Scopus and 83 articles were selected after curation. Among these studies, 72% used in vivo models and 30% used in vitro models. Additionally, 48% used the active ingredient, and 35% used commercial formulations in exposure experiments. The most affected biomarkers were related to a decrease in antioxidant capacity through alterations in the activities of catalase, superoxide dismutase and the levels of malondialdehyde. Changes in energy metabolism, lipids, liver function, and xenobiotic metabolism were also identified. Furthermore, studies about the effects of 2,4-D in mixtures with other pesticides were found, as well as hepatoprotection trials. The reviewed data indicate the essential role of reduction in antioxidant capacity and oxidative stress in 2,4-D-induced hepatotoxicity. However, the mechanism of action of the herbicide is still not fully understood and further research in this area is necessary.

Assessment toxic effects of exposure to 3-indoleacetic acid via hemato-biochemical, hormonal, and histopathological screening in rats

The current study purposed to investigate the 3-indoleacetic acid (IAA) possible adverse impacts on hematological parameters, hepatorenal function, cardiac, and skeletal muscles as well as testes of rats and histopathological alterations of respective organs and to determine the extent of reversing any adverse impacts occurred in animals after IAA withdrawal. Rats were exposed orally to 500 mg/kg BW by gastric intubation once daily for 14 days, after which one-half was sacrificed and the remaining half left for a further 14 days without IAA exposure. The exposure of rats to IAA produced anemia, leukopenia, neutrophilia, lymphopenia, and a significant increase in activities of serum transaminase, gamma-glutamyl transferase, creatine kinase-myocardial band, creatine kinase-muscle type, and levels of serum creatinine, sodium, chloride, and potassium. Furthermore, serum levels of testosterone, gonadotropins, and leptin significantly declined. The changes in most of measured parameters continued after IAA withdrawal. Histopathological alterations in different tissues supported these changes. In conclusion, subacute exposure to IAA at a high concentration could exert hematotoxicity and toxic effects on many soft organs and its withdrawal led to incomplete recovery of animals. Thus, IAA should be used cautiously as extensive use of it at high concentrations can cause harmful effects on the environment, animals and human beings.

Impacts of n-acetyl cysteine on gibberellic acid-induced hepatorenal dysfunction through modulation of pro-inflammatory cytokines, antifibrotic and antioxidant activity

The extensive usage of gibberellic acid (GA3) in agriculture and plant growth is generally associated with enormous human and public health hazards. The present research assesses the impact of n-acetyl cysteine (NAC) on the hepatorenal injury persuaded by GA3 for this purpose, After two weeks of adaptation twenty-four rats allocated into four groups (6 rats/group) as follows: control group, supplied with saline only; n-acetyl cysteine (NAC) group, provided with 150 mg/kg/bw by stomach tube (orally) dissolved in saline; Positive GA3 group, received GA3 (55 mg/kg/bw) orally; Protective group received NAC (150 mg/kg/bw) and GA3 (55 mg/kg/bw) as in NAC and GA3 groups. Rats received their treatments for consecutive 3 weeks. On day 22, rats were anesthetized, then euthanized. Blood and tissue samples were obtained for biochemical, antioxidants markers analysis, gene expression, and histopathological examination. Our results revealed significant changes in serum AST, ALT, urea, uric acid, total protein, and albumin levels with a substantial rise of MDA and NO concentration in GA3 treated rats along with a considerable decrease of the GSH and overexpression of the inflammatory hepatic and renal cytokines (IL-10, TNF-α, NOS) and fibrotic gene expression TGF-β1, and α-SMA, with boost expression of nuclear factor-kappa (NF_k B). NAC co-administered with GA3 significantly normalized the kidney and liver function and the antioxidant state, besides normal histological structure of both liver and kidney tissue and downregulated expression of the pro-inflammatory cytokines as well as, fibrogenic gene expression. PRACTICAL APPLICATIONS: The current study confirmed that GA3 induced hepto-renal dysfunction that was ameliorated by NAC administration. Moreover, our findings confirmed the antioxidant capability of n-acetyl cysteine and afford robust evidence about the ameliorative effect of the n-acetyl cysteine to attenuate the hepatorenal injury induced by gibberellic acid through modulation of the antioxidant defense system fibrogenic, and pro-inflammatory cytokines expression.

2,4-Dichlorophenoxyacetic acid induced hepatic and renal toxicological perturbations in rat model: Attenuation by selenium supplementation

2,4-Dichlorophenoxyacetic acid (2,4-D) is a commercially used herbicide to manage broadleaf weeds that have various toxicological and ecological effects. In view of ever-escalating use of 2,4-D, risk assessment becomes mandatory to ensure the safety of both human health and the ecosystem. Oxidative injury has been expected as a possible mechanism implicated in 2,4-D toxicity. The present study was planned and conducted to explore the antioxidant potential of selenium (Se) supplementation to moderate the 2,4-D hepatic and renal toxicity in a rat model. The rats were randomly assigned to four equal groups and treated via oral gavage for a period of 4 weeks. Group I: received deionized water as a vehicle, group II: received 2,4-D (150 mg^-1 kg^-1 day^-1), group III: received Se supplement (1 mg^-1 kg^-1 day^-1), and group IV: received 2,4-D (150 mg^-1 kg^-1 day^-1) and Se supplement (1 mg^-1 kg^-1 day^-1) simultaneously. After 4 weeks of administration, 2,4-D induced toxicity was observed, as manifested by disrupted levels of plasma urea, creatinine, alkaline phosphatase (ALP), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Further, 2,4-D caused a considerable increase in tissue malondialdehyde (MDA) levels and decreased activity of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione reductase. Se supplementation exhibited its antioxidant properties by significantly improving urea, creatinine, ALP, AST, and ALT, and MDA levels and antioxidant enzyme activities. In conclusion, the results suggest that 2,4-D induced hepatic and renal toxicities were attenuated by Se supplementation probably owing to its antioxidant properties.

Potential Role of Selenium Against Hepatotoxicity Induced by 2,4-Dichlorophenoxyacetic Acid in Albino Wistar Rats

The present study aims to investigate the hepatoprotective effects of selenium on toxicity induced by 'Désormone Lourd' based on 2,4-dichlorophenoxyacetic acid in Wistar rats. Male Wistar rats were divided into four groups and were treated orally. The (C) group was used as a control, while the test groups were treated with Se (0.2 mg/kg b.w.), 2,4-D (5 mg/kg b.w.) or both (2,4-D + Se) for 4 weeks. Our results showed that chronic treatment with 2,4-D resulted in hepatotoxicity, as revealed by an increase in liver function markers Aminotransferases (ALT, AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and total bilirubin (TB), along with reduced total protein content and albumin. An overall pro-oxidant effect was associated with a decrease in the reduced glutathione (GSH) content and the enzymatic activity of glutathione-S-transferase (GST), catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx), and an increase in malondialdehyde (MDA) and protein carbonyl levels (PCO). Microscopic observation of liver in 2,4-D-treated rats reveals lesions, which results in perivascular inflammatory infiltration around the vessel, sinusoidal dilatation and vacuolization of hepatocytes. However, selenium supplementation in 2,4-D-treated rats elicited a reduction in the toxic effects of the pesticide by improving the studied parameters, which was confirmed by the histological study of the liver. Selenium appears to have a promising prophylactic effect through its effective anti-radical action against the hepatotoxic effects of 2,4-D.

Magnesium supplementation ameliorates toxic effects of 2,4-dichlorophenoxyacetic acid in rat model

2,4-Dichlorophenoxyacetic acid (2,4-D) is an extensively used herbicide in the field of agriculture, its ever-escalating use induces toxicity, health effects, and environmental impact. Oxidative stress plays a key role in pathogenesis of 2,4-D-induced liver and kidney damage. Magnesium (Mg) is a highly effective antioxidant agent in restoring oxidative damage by directly influencing the metabolic and physiological processes. Therefore, the present study aimed to evaluate Mg role in ameliorating the oxidative damages provoked by 2,4-D in rat model. Male Wistar rats (180–220 g) were distributed into four groups and treated intragastrically for 4 weeks. Group 1: control, group 2: 2,4-D (150 mg/kg body weight/day), group 3: simultaneously treated with 2,4-D (150 mg/kg body weight/day) and Mg supplement (50 mg/kg body weight/day), and group 4: Mg supplement (50 mg/kg body weight/day). Under experimental conditions, plasma hepatic and renal biomarkers, tissue oxidative status, and antioxidant enzymes activities were investigated. Results demonstrated that 2,4-D intoxication caused hepatic and renal impairments as indicated by the significantly increased ( p < 0.001) alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, urea, creatinine, and blood urea nitrogen levels. In addition, 2,4-D caused a significant enhancement ( p < 0.001) in the level of malondialdehyde as well as reduction ( p < 0.001) of the superoxide dismutase, catalase, and glutathione reductase activities in both hepatic and renal tissues. Mg treatment prevented and reversed the toxic variations induced by 2,4-D. In general, these outcomes suggest that Mg may have antioxidant potential and ameliorative effects against 2,4-D provoking hepatic and renal toxicity in rat model.

The Effect of Naphthazarin on the Growth, Electrogenicity, Oxidative Stress, and Microtubule Array in Z. mays Coleoptile Cells Treated With IAA

Naphthazarin (5,8-dihydroxy-1,4-naphthoquinone, DHNQ) is a naturally occurring 1,4-naphthoquinone derivative. In this study, we focused on elucidating the toxic effect of this secondary metabolite on the growth of plant cells. The dose-response curves that were obtained for the effects of DHNQ on endogenous and IAA-induced growth in maize coleoptile segments differ in shape; in the first case, it is linear, while in the presence of auxin it is bell-shaped with the maximum at 1 μM. It was found that DHNQ at almost all concentrations studied, when added to the incubation medium inhibited endogenous growth (excluding naphthazarin at 0.001 μM) as well as growth in the presence of IAA. Simultaneous measurements of the growth and external medium pH of coleoptile segments indicated that DHNQ diminished or eliminated proton extrusion at all of the concentrations that were used. Interestingly, the oxidative stress in maize coleoptile cells, which was measured as hydrogen peroxide (H2O2) production, catalase activity, redox activity and malondialdehyde (MDA) content, increased at the lower concentrations of DHNQ (<1 μM), thus suggesting a specific character of its action. It was also found that naphthazarin at concentration higher than 0.1 μM caused the depolarization of the membrane potential (E m). An analysis of the organization and anisotropy of the cortical microtubules showed that naphthazarin at all of the concentrations that were studied changed the IAA-induced transverse microtubule reorientation to an oblique reorientation. Our results indicate that naphthazarin diminished the growth of maize coleoptile cells by a broad spectrum of its toxic effects, thereby suggesting that naphthazarin might be a hypothetical component of new bioherbicides and biopesticides.

Role of auxin (IAA) in the regulation of slow vacuolar (SV) channels and the volume of red beet taproot vacuoles

BACKGROUND

Auxin (IAA) is a central player in plant cell growth. In contrast to the well-established function of the plasma membrane in plant cell expansion, little is known about the role of the vacuolar membrane (tonoplast) in this process.

RESULTS

It was found that under symmetrical 100 mM K⁺ and 100 μM cytoplasmic Ca²⁺ the macroscopic currents showed a typical slow activation and a strong outward rectification of the steady-state currents. The addition of IAA at a final concentration of 1 μM to the bath medium stimulated the SV currents, whereas at 0.1 and 10 μM slight inhibition of SV currents was observed. The time constant, τ, decreased in the presence of this hormone. When single channels were analyzed, an increase in their activity was recorded with IAA compared to the control. The single-channel recordings that were obtained in the presence of IAA showed that auxin increased the amplitude of the single-channel currents. Interestingly, the addition of IAA to the bath medium with the same composition as the one that was used in the patch-clamp experiments showed that auxin decreased the volume of the vacuoles.

CONCLUSIONS

It is suggested that the SV channels and the volume of red beet taproot vacuoles are modulated by auxin (IAA).

Exposure to the herbicide 2,4-D produces different toxic effects in two different phytoplankters: A green microalga (Ankistrodesmus falcatus) and a toxigenic cyanobacterium (Microcystis aeruginosa)

The extensive use of 2,4-dichlorophenoxiacetic acid (2,4-D) in agriculture is an important source of pollution to water and soil. Toxicity of commonly used herbicides to non-target, planktonic photosynthetic organisms has not been described completely yet. Therefore, we determined the effect of subinhibitory 2,4-D concentrations on the Chlorophycean alga Ankistrodesmus falcatus and on a toxigenic strain of the cyanobacterium Microcystis aeruginosa. Population growth, photosynthetic pigments, macromolecular biomarkers (carbohydrates, lipids, and protein), and antioxidant enzymes (catalase [CAT], glutathione peroxidase [GPx], and superoxide dismutase [SOD]) were quantified, and the integrated biomarker response (IBR) was calculated. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations were also performed. The 96-h median inhibitory concentration (IC₅₀) for 2,4-D was 1353.80 and 71.20mgL^-1 for the alga and the cyanobacterium, respectively. Under 2,4-D stress, both organisms increased pigments and macromolecules concentration, modified the activity of all the evaluated enzymes, and exhibited ultrastructural alterations. M. aeruginosa also increased microcystins production, and A. falcatus showed external morphological alterations. The green alga was tolerant to high concentrations of the herbicide, whereas the cyanobacterium exhibited sensitivity comparable to other phytoplankters. Both organisms were tolerant to comparatively high concentrations of the herbicide; however, negative effects on the assessed biomarkers and cell morphology were significant. Moreover, stimulation of the production of cyanotoxins under chemical stress could increase the risk for the biota in aquatic environments, related to herbicides pollution in eutrophic freshwater ecosystems.

The impact of auxins used in assisted phytoextraction of metals from the contaminated environment on the alterations caused by lead(II) ions in the organization of model lipid membranes

Auxins are successfully used to improve phytoextraction efficiency of metal ions from the contaminated environment, however, the mechanism of their activity in this field is not explained. Auxins are known to exert various biochemical alterations in the plant membranes and cells, but their activity involves also direct interactions with lipids leading to changes in membrane organization. Following the suggestion that the auxins-induced modifications in membrane properties alleviate toxic effect of metal ions in this paper we have undertaken the comparative studies on the effect of metal ions and metal ions/auxins mixtures on model membrane systems. The experiments were done on lipid monolayers differing in their composition spread on water subphase and on Pb(2+), Indole-3-acetic acid (IAA), 1-Naphthaleneacetic acid (NAA) and Pb(2+)/IAA and Pb(2+)/NAA water solutions. The analysis of the collected data suggests that metal ions and auxins can change fluidity of the lipid systems and weaken the interactions between monolayer components. This manifested in the increase of the mean area per molecule and the excess area per molecule values for the films on Pb(2+), auxins as well as Pb(2+)/auxin solutions as compared to the values on pure water subphase. However, the presence of auxin in the mixture with lead(II) ions makes the alterations induced by sole metal ions weaker. This effect was more pronounced for the membranes of a higher packing. Thus it was proposed that auxins may enhance phytoextraction of metal ions by weakening their destabilizing effect on membrane.

The studies on the toxicity mechanism of environmentally hazardous natural (IAA) and synthetic (NAA) auxin--The experiments on model Arabidopsis thaliana and rat liver plasma membranes

This paper concerns the studies towards membrane-damage effect of two auxins: indole-3-acetic acid - IAA and 1-naphthaleneacetic acid - NAA on plant (Arabidopsis thaliana) and animal (rat liver) model membranes. The foregoing auxins are plant growth regulators widely used in agriculture to control the quality of the crop. However, their accumulation in the environment makes them hazardous for the living organisms. The aim of our investigations was to compare the effect of natural (IAA) vs. synthetic (NAA) auxin on the organization of plant and animal model membranes and find a possible correlation between membrane-disturbing effect of these compounds and their toxicity. The collected data evidenced that auxins cause destabilization of membranes, decrease their condensation and weakens interactions of molecules. The alterations in the morphology of model systems were also noticed. The foregoing effects of auxins are concentration-dependent and additionally NAA was found to act on animal vs. plant membranes more selectively than IAA. Interestingly, both IAA and NAA induce the strongest disordering in model lipid system at the concentration, which is frequently reported as toxic to animal and plants. Based on the above findings it was proposed that membrane-damage effect induced by IAA and NAA may be important from the point of view of the mechanism of toxicity of these compounds and cannot be ignored in further investigations in this area.

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.

Effects of sub-lethal exposure of rats to the herbicide glyphosate in drinking water: glutathione transferase enzyme activities, levels of reduced glutathione and lipid peroxidation in liver, kidneys and small intestine

Glyphosate (GLP), the active ingredient of many weed killing formulations, is a broad spectrum herbicide compound. Wistar rats were exposed during 30 or 90 days to the highest level (0.7 mg/L) of GLP allowed in water for human consumption (US EPA, 2011) and a 10-fold higher concentration (7 mg/L). The low levels of exposure to the herbicide did not produce histomorphological changes. The production of TBARS was similar or tended to be lower compared to control animals not exposed to the herbicide. In rats exposed to GLP, increased levels of reduced glutathione (GSH) and enhanced glutathione peroxidase (GPx) activity may act as a protective mechanism against possible detrimental effects of the herbicide. Overall, this work showed certain biochemical modifications, even at 3-20-fold lower doses of GLP than the oral reference dose of 2mg/kg/day (US EPA, 1993). The toxicological significance of these findings remains to be clarified.

2,4-Dichlorophenoxyacetic acid effects on nephrotoxicity in rats during late pregnancy and early postnatal periods

2,4-Dichlorophenoxyacetic acid (2,4-D) is largely used as a selective herbicide in Tunisia. The purpose of this study was to investigate the effects of 2,4-D on the kidneys of adult rats and their suckling pups. Female Wistar rats were divided into two groups: the controls and the treated rats that received 600 mg/L of 2,4-D in their drinking water from the 14th day of pregnancy until day 14 after delivery. Exposure to 2,4-D induced nephrotoxicity as evidenced by an increase in thiobarbituric acid reactive substances and protein carbonyl levels and a decrease in antioxidant enzyme activities such as catalase, superoxide dismutase, glutathione peroxidase in the kidneys of suckling pups and their mothers. In addition, a significant decline in kidney glutathione, non-protein thiol and vitamin C levels was also observed. Histological changes, seen in the kidney of mothers and their pups treated with 2,4-D are characterized by a narrowed Bowman's space, tubular epithelial cells degeneration, widened tubular lumen and vascular congestion.

Effects of olive oil and its fractions on oxidative stress and the liver's fatty acid composition in 2,4-Dichlorophenoxyacetic acid-treated rats

Background

Olive oil's beneficial effects are not only related to its high content of oleic acid, but also to the antioxidant potential of its polyphenols. In this study, we assess the effects of virgin olive oil and its fractions on 2,4-D- induced oxidative damage in the liver of rats.

Methods

Male Wistar rats were randomly divided into eight groups of ten each: (C) a control group, (D) group that received 2,4-D (5 mg/kg b.w.), (D/EVOO) group treated with 2,4-D plus extra virgin olive oil, (D/OOHF) group that received 2,4-D plus hydrophilic fraction, (D/OOLF) group treated with 2,4-D plus lipophilic fraction, (EVOO) group that received only extra virgin olive oil, (OOHF) group given hydrophilic fraction and (OOLF) group treated with lipophilic fraction. These components were daily administered by gavage for 4 weeks.

Results

A significant liver damage was observed in rats treated with 2,4-D via increased serum levels of transaminases and alkaline phosphatase, hepatic lipid peroxidation and decreased hepatic antioxidant enzyme activities, namely, superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase. The liver's fatty acid composition was also significantly modified with 2,4-D exposure. However, extra virgin olive oil and hydrophilic fraction intake during 2,4-D treatment induced a significant increase in the antioxidant enzyme activities and a decrease in the conjugated dienes (CD) and thiobarbituric acid-reactive substances (TBARs) levels in the liver. The lipophilic fraction supplemented to 2,4-D- treated rats did not show any improvement in the liver oxidative status while a marked improvement was detected in the hepatic fatty acid composition of rats supplemented with olive oil and the two fractions.

Conclusion

We concluded that the protective effect of olive oil against oxidative damage induced by 2,4-D is mainly related to the antioxidant potential of its hydrophilic fraction.

Dietary olive oil effect on antioxidant status and fatty acid profile in the erythrocyte of 2,4-D- exposed rats

Background

Oxidative stress produced by reactive oxygen species (ROS) has been linked to the development of several diseases such as cardiovascular, cancer, and neurodegenerative diseases. This study investigates the possible protective effect of extra virgin olive oil (EVOO), lipophilic fraction (OOLF) and hydrophilic fraction (OOHF) on oxidative stress and fatty acid profile of erythrocytes in 2,4-D treated rats.

Methods

Male Wistar rats were divided randomly into eight groups: control (C), (2,4-D) at a dose of 5 mg/kg b.w., (2,4-D/EVOO) was given 2,4-D plus EVOO, (2,4-D/OOHF) that received 2,4-D plus hydrophilic fraction, (2,4-D/OOLF) treated with 2,4-D plus lipophilic fraction, (EVOO) that received only EVOO, (OOHF) was given hydrophilic fraction and (OOLF) treated with lipophilic fraction. These components were daily administered by gavages for 4 weeks.

Results

2,4-D treatment lead to decrease of antioxidant enzyme activities, namely, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR) associated with a higher amount of MDA level. Erythrocyte membranes' fatty acid composition was also significantly modified with 2,4-D exposure. EVOO and hydrophilic fraction supplemented to rats with or not 2,4-D treatment enhanced the antioxidant enzyme activities and reduced the MDA level. However, lipophilic fraction did not show any improvement in oxidative damage induced by 2,4-D in spite its richness in MUFA and vitamins.

Conclusion

EVOO administered to 2,4-D-treated rats protected erythrocyte membranes against oxidative damage by means of preventing excessive lipid peroxidation to increase the MUFA composition and increase maintaining antioxidants enzymes at normal concentrations.

Determination of toxicity of subacute treatment of some plant growth regulators on rats

The effects of some plant growth regulators (PGRs), 2,3,5-triiodobenzoic acid (TIBA), Naphthaleneacetic acid (NAA) and 2,4-Dichlorofenoxyacetic acid (2,4-D), at sublethal concentrations on antioxidant defense system [glutathione peroxidases (GPx), reduced glutathione (GSH), glutathione reductase (GR), glutathione-S-transferase (GST) and catalase (CAT)], immune potential enzymes [adenosine deaminase (ADA) and myeloperoxidase (MPO)], and lipid peroxidation content [Malondialdehyde, (MDA)] were investigated in lung and speen tissues of rats. Sprague-Dawley albino rats were exposed to 0, 50, or 100 ppm (parts per million) TIBA, NAA, or 2,4-D in drinking water ad libitum for 25 days continuously. According to the results, MDA concentration significantly increased in the tissues treated with 100 ppm dosage of NAA or 2,4-D without any change in the tissues of rats treated with both dosage of TIBA. The GSH depletion in the spleen tissue of rats treated with both the dosage of NAA and 2,4-D were found to be significant. Also, GSH level in the spleen was significantly reduced with 100 ppm of 2,4-D and NAA. The activity of antioxidant enzymes were also seriously affected by PGRs; GPx significantly decreased in the lung of rats treated with both dosages of the PGRs, whereas GPx activity in the spleen were significantly increased with 100 ppm dosage of 2,4-D and NAA. On the other hand, CAT activity significantly decreased in the lung of rats treated with both dosages of NAA, 100 ppm of 2,4-D and 50 ppm of TIBA, and also in the spleen treated with 50 ppm NAA and 2,4-D. The ancillary enzyme GR activity significantly decreased in the spleen with both doses of the PGRs, also in the lung treated with both dosages of 2,4-D, 50 ppm of NAA and 100 ppm of TIBA. The drug metabolizing enzyme GST activity significantly reduced in the lung of rats treated with both dosages of the PGRs and also in the spleen treated with 100 ppm dosage of 2,4-D and TIBA and 50 ppm of NAA. Meanwhile, immune potential enzyme MPO activity significantly increased in the spleen of rats treated with both doses of NAA and TIBA whereas ADA activity significantly decreased in the spleen of rats treated with 100 ppm dose of NAA and TIBA. The observations presented led us to conclude that the administrations of subacute NAA, 2,4-D, and TIBA promote MDA content, inhibit the antioxidative defense system and activate or inhibit immune potential enzymes in the rat's spleen and lung tissues. These data suggest that PGRs produced substantial organ toxicity in the lung and spleen during the period of a 25-day subacute exposure.

Abcisic acid and gibberellic acid cause increased lipid peroxidation and fluctuated antioxidant defense systems of various tissues in rats

The study was aimed at demonstrating changes in the antioxidant defense systems [Reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] forming an antioxidative barrier and oxidative stress parameter (Malondialdehyde=MDA) in the various tissues of Sprague-Dawley rats which were administrated plant growth regulators (PGRs) [Abcisic acid (ABA) and Gibberellic acid (GA(3))] during 25 days. Seventy five parts per million of ABA and GA(3) as drinking water were administered orally to rats (Sprague-Dawley albino) ad libitum for 25 days continuously. The PGRs treatments caused different effects on antioxidant defense systems and MDA content of experimented rats compared to controls. The lipid peroxidation end product MDA significantly increased in the spleen and lungs of rats treated with ABA and GA(3) without significantly change in the other tissues. The GSH levels were significantly increased in the lungs and stomach of rats treated with ABA without any change in the tissues of rats treated with GA(3). Antioxidant enzyme activities such as SOD significantly increased in the spleen of rats treated with ABA and GA(3). Meanwhile, SOD significantly increased in the kidney of rats treated with GA. CAT significantly decreased in the lungs treated with ABA but did not change significantly in all the rest of rat tissues treated with both the PGRs. On the other hand, the ancillary enzyme GR activity decreased in the spleen and increased in the kidney with GA(3) treatment. The drug metabolizing enzyme GST activity significantly decreased in the heart of rats treated with GA(3) but increased in the spleen and lungs of rats treated with both PGRs. The observations presented led us to conclude that administration of subacute ABA and GA(3) promotes lipid peroxidatin content and alters in the antioxidative systems in the rat's various tissues. These data, along with changes, suggest that the PGRs produced oxidative stress in rats during the period of a 25-day subchronic exposure.

Lack of effects of 2,4-dichlorophenoxyacetic acid administration on markers of oxidative stress during early pregnancy in mice

Induction of oxidative stress by 2,4-dichlorophenoxyacetic acid (2,4-D) both as a pure compound and in commercial formulation was investigated during early pregnancy in mice. Pregnant animals were exposed to increasing doses of the herbicide (0.01, 0.1 and 100mg/kg/d) during gestation days 0-9, after which animals were euthanized and their blood analyzed for catalase activity, thiobarbituric acid reactive substances (TBARs) and total antioxidant capacity (TAC). Number of corpora lutea and uterine implantations and resorptions were also determined. Herbicide exposure did not cause any overt signs of maternal toxicity at any of the doses administered; neither did it cause an effect on developmental parameters. Catalase activity and TBARs were not modified by herbicide exposure although TAC was significantly decreased at 100mg/kg/d of both pure and formulated compound. Thus, 2,4-D does not seem to induce oxidative stress during early pregnancy in mice at the doses administered, indicating that this mechanism is probably not involved in mediating herbicide toxicity at these dose levels. Furthermore, since no manifestations of developmental toxicity were observed after administration of the herbicide, it is also possible that 2,4-D may not produce any early developmental toxicity at the low environmentally relevant doses tested in this animal model.