In vitro effect of methanol on folate-deficient rat hepatocytes

Biochemical mechanism underlying the pathogenesis of diabetic retinopathy and other diabetic complications in humans: the methanol-formaldehyde-formic acid hypothesis

Hyperglycemia in diabetic patients is associated with abnormally-elevated cellular glucose levels. It is hypothesized that increased cellular glucose will lead to increased formation of endogenous methanol and/or formaldehyde, both of which are then metabolically converted to formic acid. These one-carbon metabolites are known to be present naturally in humans, and their levels are increased under diabetic conditions. Mechanistically, while formaldehyde is a cross-linking agent capable of causing extensive cytotoxicity, formic acid is an inhibitor of mitochondrial cytochrome oxidase, capable of inducing histotoxic hypoxia, ATP deficiency and cytotoxicity. Chronic increase in the production and accumulation of these toxic one-carbon metabolites in diabetic patients can drive the pathogenesis of ocular as well as other diabetic complications. This hypothesis is supported by a large body of experimental and clinical observations scattered in the literature. For instance, methanol is known to have organ- and species-selective toxicities, including the characteristic ocular lesions commonly seen in humans and non-human primates, but not in rodents. Similarly, some of the diabetic complications (such as ocular lesions) also have a characteristic species-selective pattern, closely resembling methanol intoxication. Moreover, while alcohol consumption or combined use of folic acid plus vitamin B is beneficial for mitigating acute methanol toxicity in humans, their use also improves the outcomes of diabetic complications. In addition, there is also a large body of evidence from biochemical and cellular studies. Together, there is considerable experimental support for the proposed hypothesis that increased metabolic formation of toxic one-carbon metabolites in diabetic patients contributes importantly to the development of various clinical complications.

Long-Term Effect of Aspartame on Male Reproductive System: Evidence for Testicular Histomorphometrics, Hsp70-2 Protein Expression and Biochemical Status

Background

Aspartame is one of the most commonly consumed artificial sweeteners that is widely used in foodstuffs. There are many debatable reports about aspartame toxicity in different tissues; however, on the subject of its effects on the reproductive system, few literatures are available. The present study was carried out for evaluating effects of aspartame on the reproductive system in male mice.

Materials and Methods

In this experimental study, a total of 36 adult male mice were randomly divided into four groups of nine animals each. Three groups received aspartame at doses of 40, 80 and 160 mg/kg (gavage) for 90 days; also, a control group was considered. Twenty-four hours after the last treatment, animals were sacrificed. Then, body and testis weights, sperm parameters, serum testosterone concentration, total antioxidant capacity, and malondialdehyde (MDA) levels, antioxidant enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px)] activities in blood, histomorphometrical indices and histochemical changes in testis were evaluated; also, mRNA and immunohistochemical expression of Hsp70-2 was measured in testis tissue.

Results

The results revealed remarkable differences in sperm parameters, testosterone and oxidative stress biomarkers levels, and histomorphometrical indices, between the control and treatment groups. Also, in 80 and 160 mg/kg aspartametreated groups, expression of Hsp70-2 was decreased. Besides, in the aspartame receiving groups, some histochemical changes in testicular tissue were observed.

Conclusion

The findings of the present study elucidated that long-term consumption of aspartame resulted in reproductive damages in male mice through induction of oxidative stress.

Vitamin E Reversed Apoptosis of Cardiomyocytes Induced by Exposure to High Dose Formaldehyde During Mice Pregnancy

In this study, we investigated the protection effect of Vitamin E (Vit E) on formaldehyde (FA) exposure during pregnancy induced apoptosis of cardiomyocytes, and used an HL-1 cell line to confirmed the findings in vivo.Pregnant mice received different doses of FA (0.5 mg/kg, 1.0 mg/kg, 1.5 mg/kg, 0.1 μg Vit E, or 1.5 mg/kg + 0.1 μg Vit E). TUNEL staining was used to reveal the apoptosis in cardiomyocytes, and SOD, MDA, GSH, Livin, and Caspase-3 in cardiomyocytes were detected by ELISA, RT-PCR, and Western blot. For in vitro study, HL-1 cells were treated with vehicle, 5 μmol/L FA, 25 μmol/L FA, 50 μmol/L FA, 10 mg/L Vit. E, and 50 μmol/L FA+ 10 mg/L Vit E, respectively. CCK-8 assay and flow cytometry were used to evaluate cell vitality and apoptosis. A high dose of FA exposure led to cytotoxicity in both pregnant mice and offspring, as TUNEL staining revealed a significant apoptosis of cardiomyocytes, and the alternation in SOD, GSH, MDA, Livin, and Caspase-3 was found in cardiomyocytes. 0.1 μg Vit. E could reverse high doses of FA exposure induced apoptosis of cardiomyocytes in both pregnant mice and offspring. The in vitro study revealed that FA exposure induced a decrease of cell viability and increased cell apoptosis, as well as oxidative stress in HL-1 cells with alternation in SOD, GSH, MDA, Livin, and Caspase-3.This study revealed a high dose of FA induced oxidative stress and apoptosis of cardiomyocytes in both pregnant mice and offspring, and Vit E supplement during pregnancy reversed the systemic and myocardial toxicity of FA.

Formaldehyde-induced toxicity in the nasal epithelia of workers of a plastic laminate plant

Formaldehyde is a ubiquitous volatile organic compound widely used for various industrial purposes. Formaldehyde was reclassified by the International Agency for Research on Cancer as a human carcinogen, based on sufficient evidence for a casual role for nasopharyngeal cancer. However, the mechanisms by which this compound causes nasopharyngeal cancer are not completely understood. Therefore, we have examined the formaldehyde-induced toxicity in the nasal epithelia of the workers of a plastic laminate plant in Bra, Cuneo, Piedmont region, North-Western Italy, hence in the target site for formaldehyde-related nasal carcinogenesis. We have conducted a cross-sectional study aimed at comparing the frequency of 3-(2-deoxy-β-d-erythro-pentafuranosyl)pyrimido[1,2-α]purin-10(3H)-one deoxyguanosine (M1dG) adducts, a biomarker of oxidative stress and lipid peroxidation, in 50 male exposed workers and 45 male controls using 32P-DNA post-labeling. The personal levels of formaldehyde exposure were analysed by gas-chromatography mass-spectrometry. The smoking status was estimated by measuring the concentrations of urinary cotinine by gas-chromatography mass-spectrometry. The air monitoring results showed that the exposure levels of formaldehyde were significantly greater for the plastic laminate plant workers, 211.4 ± 14.8 standard error (SE) μg m-3, than controls, 35.2 ± 3.4 (SE) μg m-3, P < 0.001. The levels of urinary cotinine were 1064 ± 118 ng ml-1 and 14.18 ± 2.5 ng ml-1 in smokers and non-smokers, respectively, P < 0.001. The M1dG adduct frequency per 108 normal nucleotides was significantly higher among the workers of the plastic laminate plant exposed to formaldehyde, 111.6 ± 14.3 (SE), compared to controls, 49.6 ± 3.4 (SE), P < 0.001. This significant association persisted also when personal dosimeters were used to measure the extent of indoor levels of formaldehyde exposure. No influences of smoking and age were observed across the study population. However, after categorization for occupational exposure, a significant effect was found in the controls, P = 0.018, where the levels of DNA damage were significantly correlated with the levels of urinary cotinine, regression coefficient (β) = 0.494 ± 0.000 (SE), P < 0.002. Our findings indicated that M1dG adducts constitute a potential mechanism of formaldehyde-induced toxicity. Persistent DNA damage contributes to the general decline of the physiological mechanisms designed to maintain cellular homeostasis.

Oxidative effects on lung inflammatory response in rats exposed to different concentrations of formaldehyde

The formaldehyde (FA) is a crosslinking agent that reacts with cellular macromolecules such as proteins, nucleic acids and molecules with low molecular weight such as amino acids, and it has been linked to inflammatory processes and oxidative stress. This study aimed to analyze the oxidative effects on pulmonary inflammatory response in Fischer rats exposed to different concentrations of FA. Twenty-eight Fischer rats were divided into 4 groups (N = 7). The control group (CG) was exposed to ambient air and three groups were exposed to different concentrations of FA: 1% (FA1%), 5% (FA5%) and 10% (FA10%). In the Bronchoalveolar Lavage Fluid (BALF), the exposure to a concentration of 10% promoted the increase of inflammatory cells compared to CG. There was also an increase of macrophages and lymphocytes in FA10% and lymphocytes in FA5% compared to CG. The activity of NADPH oxidase in the blood had been higher in FA5% and FA10% compared to CG. The activity of superoxide dismutase enzyme (SOD) had an increase in FA5% and the activity of the catalase enzyme (CAT) showed an increase in FA1% compared to CG. As for the glutathione system, there was an increase in total glutathione (tGSH), reduced glutathione (GSH) and oxidized glutathione (GSSG) in FA5% compared to CG. The reduced/oxidized glutathione ratio (GSH/GSSG) had a decrease in FA5% compared to CG. There was an increase in lipid peroxidation compared to all groups and the protein carbonyl formation in FA10% compared to CG. We also observed an increase in CCL2 and CCL5 chemokines in the treatment groups compared to CG and in serum there was an increase in CCL2, CCL3 and CCL5 compared to CG. Our results point out to the potential of formaldehyde in promoting airway injury by increasing the inflammatory process as well as by the redox imbalance.

Central nervous system toxicity after acute oral formaldehyde exposure in rabbits

Formaldehyde (FA) is one of the most widely used chemical compounds in industrial field. It is described as toxic, particularly to the nervous system, the urogenital system, and the respiratory tracts. In this study, we determined the effects of acute oral exposure to FA in rabbit brain tissue. A total of 16 rabbits were selected and divided into 2 groups: formaldehyde group (group F) and control group (group C). FA was administered to group F at a rate of 40 mg/kg/day via a nasogastric tube for 5 days. Saline was similarly administered to the eight controls. All the animals were euthanized after 5 days of exposure, and brain tissue samples were collected in 10% neutral formalin and embedded in paraffin. To investigate the effects of FA on the apoptotic process, we examined active caspase-3, Bax, and Bcl-2 immunohistochemical expression and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate –biotin nick-end labeling (TUNEL) reactivity in the rabbit brains. In addition, glial fibrillary acidic protein (GFAP) was biochemically assessed in brain tissue samples for neurotoxicity. We found that FA treatment caused a significant decrease in Bcl-2 expression and an increase in active caspase-3 and Bax expressions as well as an increase in the number of TUNEL-positive apoptotic cells. The GFAP level was found to be significantly higher in group F. In conclusion, acute oral exposure to FA caused DNA damage, apoptosis, and neuronal injury in the rabbit brains.

Methanol may function as a cross-kingdom signal

Recently, we demonstrated that leaf wounding results in the synthesis of pectin methylesterase (PME), which causes the plant to release methanol into the air. Methanol emitted by a wounded plant increases the accumulation of methanol-inducible gene mRNA and enhances antibacterial resistance as well as cell-to-cell communication, which facilitates virus spreading in neighboring plants. We concluded that methanol is a signaling molecule involved in within-plant and plant-to-plant communication. Methanol is considered to be a poison in humans because of the alcohol dehydrogenase (ADH)-mediated conversion of methanol into toxic formaldehyde. However, recent data showed that methanol is a natural compound in normal, healthy humans. These data call into question whether human methanol is a metabolic waste product or whether methanol has specific function in humans.

Here, to reveal human methanol-responsive genes (MRGs), we used suppression subtractive hybridization cDNA libraries of HeLa cells lacking ADH and exposed to methanol. This design allowed us to exclude genes involved in formaldehyde and formic acid detoxification from our analysis. We identified MRGs and revealed a correlation between increases in methanol content in the plasma and changes in human leukocyte MRG mRNA levels after fresh salad consumption by volunteers. Subsequently, we showed that the methanol generated by the pectin/PME complex in the gastrointestinal tract of mice induces the up- and downregulation of brain MRG mRNA. We used an adapted Y-maze to measure the locomotor behavior of the mice while breathing wounded plant vapors in two-choice assays. We showed that mice prefer the odor of methanol to other plant volatiles and that methanol changed MRG mRNA accumulation in the mouse brain.

We hypothesize that the methanol emitted by wounded plants may have a role in plant-animal signaling. The known positive effect of plant food intake on human health suggests a role for physiological methanol in human gene regulation.

Fatal methanol poisoning

Methanol poisoning has become a considerable problem in Iran. Liver can show some features of poisoning after methanol ingestion. Therefore, our concern was to examine liver tissue histopathology in fatal methanol poisoning cases in Iranian population. In this study, 44 cases of fatal methanol poisoning were identified in a year. The histological changes of the liver were reviewed. The most striking features of liver damage by light microscopy were micro-vesicular steatosis, macro-vesicular steatosis, focal hepatocyte necrosis, mild intra-hepatocyte bile stasis, feathery degeneration and hydropic degeneration. Blood and vitreous humor methanol concentrations were examined to confirm the proposed history of methanol poisoning. The majority of cases were men (86.36%). In conclusion, methanol poisoning can cause histological changes in liver tissues. Most importantly in cases with mean blood and vitreous humor methanol levels greater than 127 ± 38.9 mg/dL more than one pathologic features were detected.

Fatal methanol poisoning: features of liver histopathology

Methanol poisoning has become a considerable problem in Iran. Liver can show some features of poisoning after methanol ingestion. Therefore, our concern was to examine liver tissue histopathology in fatal methanol poisoning cases in Iranian population. In this study, 44 cases of fatal methanol poisoning were identified in a year. The histological changes of the liver were reviewed. The most striking features of liver damage by light microscopy were micro-vesicular steatosis, macro-vesicular steatosis, focal hepatocyte necrosis, mild intra-hepatocyte bile stasis, feathery degeneration and hydropic degeneration. Blood and vitreous humor methanol concentrations were examined to confirm the proposed history of methanol poisoning. The majority of cases were men (86.36%). In conclusion, methanol poisoning can cause histological changes in liver tissues. Most importantly in cases with mean blood and vitreous humor methanol levels greater than 127 ± 38.9 mg/dL more than one pathologic features were detected.

Differential oxidative stress responses to methanol in intraperitoneally exposed rats: ameliorative effects of Opuntia vulgaris fruit extract

Methanol is primarily metabolized by oxidation to formaldehyde and then to formate. These processes are accompanied by formation of superoxide anion and hydrogen peroxide. This article reports data on the effect of methanol-induced oxidative damage in experimental rats and the role of aqueous extract of Opuntia vulgaris fruit extract (OE) to counteract the toxicity induced by methanol. The animals were exposed to methanol at a dose of 2.37 g/kg body weight intraperitoneally for 30 days. OE was found to contain large amounts of polyphenols and carotenoids and significant antioxidant capacities highlighted by scavenging activities for 2,2-diphenyl-l-picrylhydrazyl. The treatment with methanol exhibited a significant increase in serum hepatic and renal biochemical parameters (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, bilirubin, urea, and creatinine). Methanol intoxication significantly increased hepatic and renal lipid peroxidation evaluated by thiobarbituric acid reactive substances in treated rats as compared to controls. However, hepatic and renal antioxidant enzymes namely superoxide dismutase, catalase, and glutathione peroxidase were significantly decreased in methanol-treated animals as compared to controls. The results concluded that treatment with OE prior to methanol intoxication has significant role in protecting animals from methanol-induced hepatic and renal histopathological and oxidative damage.

Malondialdehyde-deoxyguanosine adduct formation in workers of pathology wards: the role of air formaldehyde exposure

Formaldehyde is an ubiquitous pollutant to which humans are exposed. Pathologists can experience high formaldehyde exposure levels. Formaldehyde-among other properties-induce oxidative stress and free radicals, which react with DNA and lipids, leading to oxidative damage and lipid peroxidation, respectively. We measured the levels of air-formaldehyde exposure in a group of Italian pathologists and controls. We analyzed the effect of formaldehyde exposure on leukocyte malondialdehyde-deoxyguanosine adducts (M(1)-dG), a biomarker of oxidative stress and lipid peroxidation. We studied the relationship between air-formaldehyde and M(1)-dG adducts. Air-formaldehyde levels were measured by personal air samplers. M(1)-dG adducts were analyzed by a (32)P-postlabeling assay. Reduction room pathologists were significantly exposed to air-formaldehyde with respect to controls and to the pathologists working in other laboratory areas (p < 0.001). A significant difference for M(1)-dG adducts between exposed pathologists and controls was found (p = 0.045). The effect becomes stronger when the evaluation of air-formaldehyde exposure was based on personal samplers (p = 0.018). Increased M(1)dG adduct levels were only found in individuals exposed to air-formaldehyde concentrations higher than 66 microg/m(3). When the exposed workers and controls were subgrouped according to smoking, M(1)-dG tended to increase in all of the subjects, but a significant association between M(1)-dG and air-formaldehyde was only found in nonsmokers (p = 0.009). Air-formaldehyde played a role positive but not significant (r = 0.355, p = 0.075, Pearson correlation) in the formation of M(1)-dG, only in nonsmokers. Working in the reduction rooms and exposure to air-formaldehyde concentrations higher than 66 microg/m(3) are associated with increased levels of M(1)-dG adducts.

Effect of lycopene on caspase-3 enzyme activation in liver of methanol-intoxicated rats: comparison with fomepizole

Lycopene is one of the major carotenoids and is found almost exclusively in tomatoes and tomato products. This study was performed to evaluate the effect of lycopene on methanol-induced liver injury and to compare the results with those after fomepizole, which is used in treatment of methanol intoxication. Experiments were carried out with 30 female Wistar rats weighting 180-200 g. Rats were injected with a intraperitoneally dose of 3 g/kg methanol as a 50% solution in isotonic saline once for intoxication. Rats were pretreated with fomepizole (50 mg/kg) and/or lycopene (10 mg/kg) before methanol. After 24 hours all the drug-treated and intoxicated rats were sacrificed under anesthesia. Malondialdehyde (MDA) levels were determined in order to assess lipid peroxidation, and caspase-3 activity was determined by immunostaining of liver tissues to evaluate apoptosis. Methanol administration significantly increased the MDA level and caspase-3 activity in liver. Pretreatment with lycopene and/or fomepizole decreased the MDA levels significantly. Similarly, lycopene and fomepizole decreased methanol-induced caspase-3 activity. The findings of the present study demonstrate that methanol intoxication causes hepatic toxicity in rats and that this is likely a result of reactive oxygen species and apoptosis induction. Lycopene has protective effects against methanol-induced hepatic injury similar to fomepizole. It was demonstrated for the first time that both lycopene and fomepizole prevent methanol-induced hepatic injury by reducing the increase of lipid oxidation and caspase-3 activation.

The toxic effects of formaldehyde on the nervous system

Formaldehyde (FA) is found in the polluted atmosphere of cities, domestic air (e.g., paint, insulating materials, chipboard and plywood, fabrics, furniture, paper), and cigarette smoke, etc.; therefore, everyone and particularly susceptible children may be exposed to FA. FA is also widely used in industrial and medical settings and as a sterilizing agent, disinfectant, and preservative. Therefore, employees may be highly exposed to it in there settings. Of particular concern to the authors are anatomists and medical students, who can be highly exposed to formaldehyde vapor during dissection sessions. Formaldehyde is toxic over a range of doses; chances of exposure and subsequent harmful effects are increased as (room) temperature increases, because of FA's volatility. Many studies have been conducted to evaluate the effects of FA during systemic and respiratory exposures in rats. This review compiles that literature and emphasizes the neurotoxic effects of FA on neuronal morphology, behavior, and biochemical parameters. The review includes the results of some of the authors' work related to FA neurotoxicity, and such neurotoxic effects from FA exposure were experimentally demonstrated. Moreover, the effectiveness of some antioxidants such as melatonin, fish omega-3, and CAPE was observed in the treatment of the harmful effects of FA. Despite the harmful effects from FA exposure, it is commonly used in Turkey and elsewhere in dissection laboratories. Consequently, all anatomists must know and understand the effects of this toxic agent on organisms and the environment, and take precautions to avoid unnecessary exposure. The reviewed studies have indicated that FA has neurotoxic characteristics and systemic toxic effects. It is hypothesized that inhalation of FA, during the early postnatal period, is linked to some neurological diseases that occur in adults. Although complete prevention is impossible for laboratory workers and members of industries utilizing FA, certain precautions can be taken to decrease and/or prevent the toxic effects of FA.

Excessive S-adenosyl-L-methionine-dependent methylation increases levels of methanol, formaldehyde and formic acid in rat brain striatal homogenates: possible role in S-adenosyl-L-methionine-induced Parkinson's disease-like disorders

AIMS

Excessive methylation may be a precipitating factor for Parkinson's disease (PD) since S-adenosylmethionine (SAM), the endogenous methyl donor, induces PD-like changes when injected into the rat brain. The hydrolysis of the methyl ester bond of the methylated proteins produces methanol. Since methanol is oxidized into formaldehyde, and formaldehyde into formic acid in the body, we investigated the effects of SAM on the production of methanol, formaldehyde and formic acid in rat brain striatal homogenates and the toxicity of these products in PC12 cells.

MAIN METHODS

Radio-enzymatic and colorimetric assays, cell viability, Western blot.

KEY FINDINGS

SAM increased the formation of methanol, formaldehyde and formic acid in a concentration and time-dependent manner. Concentrations of [3H-methyl]-SAM at 0.17, 0.33, 0.67 and 1.34 nM produced 3.8, 8.0, 18.3 and 34.4 fmol/mg protein/h of [3H] methanol in rat striatal homogenates, respectively. SAM also significantly generated formaldehyde and formic acid in striatal homogenates. Formaldehyde was the most toxic metabolite to differentiated PC12 pheochromocytoma cells in cell culture studies, indicating that formaldehyde formed endogenously may contribute to neuronal damage in excessive methylation conditions. Subtoxic concentration of formaldehyde decreased the expression of tyrosine hydroxylase, the limiting factor in dopamine synthesis. Formaldehyde was more toxic to catecholaminergic PC12 cells than C6 glioma cells, indicating that neurons are more vulnerable to formaldehyde than glia cells.

SIGNIFICANCE

We suggest that excessive carboxylmethylation of proteins might be involved in the SAM-induced PD-like changes and in the aging process via the toxic effects of formaldehyde.

Melatonin improves methanol intoxication-induced oxidative liver injury in rats

This study was performed to evaluate the effect of melatonin on methanol-induced liver injury. We evaluated the levels of malondialdehyde (MDA), protein carbonylation (PC), myeloperoxidase (MPO) activities and to assess lipid peroxidation, protein oxidation, neutrophil accumulation and nitrite which is a stable end product of nitric oxide respectively. We also studied superoxide dismutase, catalase, and glutathione peroxidase activities of liver tissue to evaluate the changes in the antioxidant status. Histopathological alterations were also determined. The experiment was performed on Wistar rats, which received intragastric 3 g/kg methanol as a 50% solution in isotonic saline once. After 6 and 24 hr all the drug received and intoxicated rats were killed under anesthesia. Pretreatment with melatonin (10 mg/kg) decreased the MDA levels significantly, restored the PC levels to the control, prevented the increase of nitrite level and MPO activity significantly and reversed to the control levels, prevented the reduction in all of the antioxidant enzyme activities. Additionally in melatonin treated group piecemeal necrosis, lobular lytic necrosis, and portal inflammation returned to normal histologic appearances when compared with methanol administration. In conclusion, melatonin has protective effects against methanol-induced hepatic injury.

Efficacy of dl-α-lipoic acid on methanol induced free radical changes, protein oxidative damages and hsp70 expression in folate deficient rat nervous tissue

DL-alpha-Lipoic acid (LPA) was reported to be effective in reducing free radicals generated by oxidative stress. The protective of effect of LPA on methanol (MeOH) induced free radical changes and oxidative damages in discrete regions of rat brain have been reported in this study. Folate deficient rat (FDD) model was used. The five animal groups (saline control, FDD control, FDD+MeOH, FDD+LPA+MeOH, LPA control) were used. The FDD+MeOH and FDD+LPA+MeOH animals were injected intraperitoneally with methanol (3gm/kg). After 24h, the level of free radical scavengers such as, superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione was estimated in six discrete regions of brain, retina and optic nerve. Level of protein thiol, protein carbonyl and lipid peroxidation was also estimated. Expression of heat shock protein 70 mRNA (hsp70) was studied in the cerebellum and hippocampus by reverse transcriptase PCR. All the samples showed elevation in the level of free radical scavenging enzymes and reduced level of glutathione in the FDD+MeOH group in relation to the other groups. hsp70 expression was more in FDD+MeOH group when compared to FDD+LPA+MeOH group. In conclusion, MeOH exposure leads to increased free radical generation and protein oxidative damages in the rat nervous tissue. Treatment with LPA prevents oxidative damage induced by MeOH exposure.

Protective effect of α-tocopherol on oxidative stress in experimental pulmonary fibrosis in rats

The study was undertaken to investigate the influence of alpha-tocopherol (vitamin E) on malondialdehyde (MDA) and glutathione (GSH) levels and catalase (CAT) activity in lung of rats with bleomycin-induced pulmonary fibrosis (PF). Fourteen Wistar-albino rats were randomly divided into two groups of seven animals each. The first group was treated intra-tracheally with bleomycin hydrochloride (BM group); the second group was also instilled with BM but received injections of alpha-tocopherol twice a week (BM + E group). The third group was treated in the same manner with saline solution only, acting as controls (C). There were decreases in GSH level and CAT activity while an increase in MDA level in BM group was found compared to the control group (p < 0.05). Vitamin E had a regulator effect on these parameters. After administration of alpha-tocopherol, the increase in GSH level and CAT activity and the decrease in MDA level were seen in BM + E group compared to BM group (p < 0.05). Distinct histopathological changes were found in the BM group compared to the untreated rats. Less severe fibrotic lesions were also observed in the BM + E group. The results show that vitamin E is effective on the prevention of BM-induced PF, as indicated by differences in the lung levels of oxidants and antioxidants.

Vitamin E Protects Against Oxidative Damage Caused by Formaldehyde in the Liver and Plasma of Rats

It is well known that formaldehyde (FA) and reactive oxygen species (ROS) are cytotoxic and potentially carcinogenic. Although the individual effects of these reactants on cells have been investigated, the cytotoxicity exerted by the coexistence of FA and ROS is poorly understood. The present study was carried out to evaluate oxidant/antioxidant status and biochemical changes occurring after chronic formaldehyde toxicity in liver tissue and plasma of rats and protective effect of vitamin E (vit E) against oxidative damage. Eighteen rats were divided into three groups: (1) control rats, (2) rats treated with FA (FAt), and (3) rats treated with FA plus vit E (FAt + vit E) groups. After the treatment, the animals were sacrificed and liver tissues were removed for biochemical investigations. As a result, FA treatment significantly increased the levels of tissue malondialdehyde (MDA), protein carbonyl (PC), nitric oxide (NO) and the activity of xanthine oxidase enzyme (XO). On the other hand, FA exposure led to decrease in superoxide dismutase (SOD) and catalase (CAT) activities in liver tissues compared to control. FA caused significant decreases in total protein (TP) and albumin (ALB) whereas increases in aspartate transaminase (AST), alanine aminotransferase (AST), alkaline phosphatase (ALP) and interleukine-2 (IL-2) levels in plasma. Vit E treatment abolished these changes at a level similar to the control group. It was concluded that vit E treatment might be beneficial in preventing FA-induced liver tissue damage, and therefore have potential for clinical use.

Vitamin E against oxidative damage caused by formaldehyde in frontal cortex and hippocampus: Biochemical and histological studies

Formaldehyde (FA) can cause severe central nervous system impairment. But, there are only a few studies about biochemical and histopathological changes of frontal cortex and hippocampal tissue caused by FA toxicity. The aim of our study was to investigate these changes occurring after chronic formaldehyde toxicity in frontal cortex and hippocampal tissues, and protective effect of Vitamin E (vit E) against oxidative damage. Eighteen rats were divided into three groups: (1) control, (2) treated with FA (FAt), and (3) treated with FA and vit E (FAt+vit E) groups. After the treatment, the animals were sacrificed and frontal cortex and hippocampal tissues were removed for biochemical and histopathological investigation. FA significantly increased tissue malondialdehyde (MDA) and protein carbonyl (PC) levels and also decreased superoxide dismutase (SOD) and catalase (CAT) enzyme activities in frontal cortex and hippocampal tissue compared to control. Vit E treatment decreased MDA and PC levels and prevented inhibition of SOD and CAT enzymes in the tissues. In the FAt group, the neurons of both tissues became extensively dark and degenerated with picnotic nuclei. The morphology of neurons in FAt+vit E group was protected well, but not as neurons of the control group. The number of neurons in frontal cortex and hippocampal tissue of FAt group was significantly less than both control and FAt+vit E groups. It was concluded that vit E treatment might be beneficial in preventing FA-induced oxidative frontal cortex and hippocampal tissue damage, therefore, shows potential for clinical use.