Protection by Neostigmine and Atropine Against Brain and Liver Injury Induced by Acute Malathion Exposure.

We examined the effect of treatment with neostigmine alone or with atropine on brain oxidative stress and on brain and liver tissue damage following acute malathion toxicity. Rats were intraperitoneally treated with malathion 150 mg/kg along with neostigmine (200 or 400 µg/kg) or neostigmine (200 µg/kg) + atropine (1 mg/kg) and euthanized 4 h later. Results indicated that compared with the saline group, malathion resulted in (i) higher brain malondialdehyde (MDA) and nitric oxide (46.4% and 86.2%); (ii) decreased brain reduced glutathione (GSH) (67.6%); (iii) decreased brain paraoxonase-1 (PON1), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities (31.2%, 21.6% and 60%); (iv) decreased brain glucose (-38.1%); (v) neuronal degeneration in cortex and hippocampus and markedly increased glial fibrillary acidic protein (GFAP) immunostaining in the hippocampus; (v) hydropic and fatty degeneration in liver. Rats treated with malathion along with neostigmine or neostigmine + atropine showed no change in brain MDA but decreased nitric oxide (-34.2%-48%). GSH increased after neostigmine 200 µg/kg or neostigmine + atropine (35.8% and 41%). PON1 activity increased (42%-35.2%) and glucose concentrations increased (91.5%-81.5%) by 400 µg/kg neostigmine or neostigmine + atropine. Brain AChE activity remained unchanged but BChE activity showed 18.3% increment after 400 µg/kg neostigmine. Rats treated with 400 µg/kg neostigmine or neostigmine + atropine had normal neuronal appearance in cortex and hippocampus and weak GFAP expression in hippocampus. Liver damage was prevented by neostigmine + atropine. These results suggest that treatment with neostigmine + atropine afforded protection against the deleterious effects of acute malathion on the brain and liver.

Nitric oxide synthase inhibitors protect against brain and liver damage caused by acute malathion intoxication.

OBJECTIVE: To investigate the effect of NG-nitro-l-arginine methyl ester (l-NAME), a non-selective nitric oxide synthase (NOS) inhibitor, and 7-nitroindazole (7-NI), a selective neuronal NOS inhibitor, on oxidative stress and tissue damage in brain and liver and on DNA damage of peripheral blood lymphocytes in malathion intoxicated rats. METHODS: Malathion (150 mg/kg) was given intraperitoneally (i.p.) along with l-NAME or 7-NI (10 or 20 mg/kg, i.p.) and rats were euthanized 4 h later. The lipid peroxidation product malondialdehyde (MDA), nitric oxide (nitrite), reduced glutathione (GSH) concentrations and paraoxonase-1 (PON-1) activity were measured in both brain and liver. Moreover, the activities of glutathione peroxidase (GPx) acetylcholinesterase (AChE), and butyrylcholinesterase (BChE), total antioxidant capacity (TAC), glucose concentrations were determined in brain. Liver enzyme determination, Comet assay, histopathological examination of brain and liver sections and inducible nitric oxide synthase (iNOS) immunohistochemistry were also performed. RESULTS: (i) Rats treated with only malathion exhibited increased nitric oxide and lipid peroxidation (malondialdehyde) accompanied with a decrease in GSH content, and PON-1 activity in brain and liver. Glutathione peroxidase activity, TAC, glucose concentrations, AChE and BChE activities were decreased in brain. There were also raised liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities and increased DNA damage of peripheral blood lymphocytes (Comet assay). Malathion caused marked histopathological changes and increased the expression of iNOS in brain and liver tissues. (ii) In brain of malathion-intoxicated rats, l-NAME or 7-NI resulted in decreased nitrite and MDA contents while increasing TAC and PON1 activity. Reduced GSH and GPx activity showed an increase by l-NAME. AChE activity increased by 20 mg/kg l-NAME and 10 mg/kg 7-NI. AChE activity decreased by the higher dose of 7-NI while either dose of 7-NI resulted in decreased BChE activity. (iii) In liver of malathion-intoxicated rats, decreased MDA content was observed after l-NAME or 7-NI. Nitrite level was unchanged by l-NAME but increased after 7-NI which also resulted in decreased GSH concentration and PON1 activity. Either inhibitor resulted in decreased liver ALT activity. (iv) DNA damage of peripheral blood lymphocytes was markedly inhibited by l-NAME or 7-NI treatment. (v) iNOS expression in brain and liver decreased by l-NAME or 7-NI. (vi) More marked improvement of the histopathological alterations induced by malathion in brain and liver was observed after 7-NI compared with l-NAME. CONCLUSIONS: In malathion intoxicated rats, the neuronal NOS inhibitor 7-NI and to much less extent l-NAME were able to protect the brain and liver tissue integrity along with improvement in oxidative stress parameters. The decrease in DNA damage of peripheral blood lymphocytes by NOS inhibitors also suggests the involvement of nitric oxide in this process.

Novel neuroprotective and hepatoprotective effects of citric acid in acute malathion intoxication.

OBJECTIVE: To study the effect of citric acid given alone or combined with atropine on brain oxidative stress, neuronal injury, liver damage, and DNA damage of peripheral blood lymphocytes induced in the rat by acute malathion exposure. METHODS: Rats were received intraperitoneal (i.p.) injection of malathion 150 mg/kg along with citric acid (200 or 400 mg/kg, orally), atropine (1 mg/kg, i.p.) or citric acid 200 mg/kg + atropine 1 mg/kg and euthanized 4 h later. RESULTS: Malathion resulted in increased lipid peroxidation (malondialdehyde) and nitric oxide concentrations accompanied with a decrease in brain reduced glutathione, glutathione peroxidase (GPx) activity, total antioxidant capacity (TAC) and glucose concentrations. Paraoxonase-1, acetylcholinesterase (AChE) and butyrylcholinesterase activities decreased in brain as well. Liver aspartate aminotransferase and alanine aminotransferase activities were raised. The comet assay showed increased DNA damage of peripheral blood lymphocytes. Histological damage and increased expression of inducible nitric oxide synthase (iNOS) were observed in brain and liver. Citric acid resulted in decreased brain lipid peroxidation and nitric oxide. Meanwhile, glutathione, GPx activity, TAC capacity and brain glucose level increased. Brain AChE increased but PON1 and butyrylcholinesterase activities decreased by citric acid. Liver enzymes, the percentage of damaged blood lymphocytes, histopathological alterations and iNOS expression in brain and liver was decreased by citric acid. Meanwhile, rats treated with atropine showed decreased brain MDA, nitrite but increased GPx activity, TAC, AChE and glucose. The drug also decreased DNA damage of peripheral blood lymphocytes, histopathological alterations and iNOS expression in brain and liver. CONCLUSIONS: The study demonstrates a beneficial effect for citric acid upon brain oxidative stress, neuronal injury, liver and DNA damage due to acute malathion exposure.

Citric acid effects on brain and liver oxidative stress in lipopolysaccharide-treated mice.

Citric acid is a weak organic acid found in the greatest amounts in citrus fruits. This study examined the effect of citric acid on endotoxin-induced oxidative stress of the brain and liver. Mice were challenged with a single intraperitoneal dose of lipopolysaccharide (LPS; 200 µg/kg). Citric acid was given orally at 1, 2, or 4 g/kg at time of endotoxin injection and mice were euthanized 4 h later. LPS induced oxidative stress in the brain and liver tissue, resulting in marked increase in lipid peroxidation (malondialdehyde [MDA]) and nitrite, while significantly decreasing reduced glutathione, glutathione peroxidase (GPx), and paraoxonase 1 (PON1) activity. Tumor necrosis factor-alpha (TNF-α) showed a pronounced increase in brain tissue after endotoxin injection. The administration of citric acid (1-2 g/kg) attenuated LPS-induced elevations in brain MDA, nitrite, TNF-α, GPx, and PON1 activity. In the liver, nitrite was decreased by 1 g/kg citric acid. GPx activity was increased, while PON1 activity was decreased by citric acid. The LPS-induced liver injury, DNA fragmentation, serum transaminase elevations, caspase-3, and inducible nitric oxide synthase expression were attenuated by 1-2 g/kg citric acid. DNA fragmentation, however, increased after 4 g/kg citric acid. Thus in this model of systemic inflammation, citric acid (1-2 g/kg) decreased brain lipid peroxidation and inflammation, liver damage, and DNA fragmentation.

Oxidative status and the response to pegylated-interferon alpha2a plus ribavirin in chronic genotype 4 HCV hepatitis.

Oxidative stress may play a pathogenic role in chronic hepatitis C (CHC). The present study examined the oxidative status in plasma of patients with CHC who received pegylated interferon and ribavirin therapy. The following groups were included: (1) sustained virological response (28 patients), (2) null response (26 patients), (3) breakthrough (24 patients), (4) relapse (24 patients), (5) spontaneous cure (23 patients) and (6) twenty five normal subjects as a control group. Markers of oxidative stress including plasma malondialdehyde, nitric oxide, reduced glutathione, total antioxidant capacity and uric acid as well as serum ALT, AST, alkaline phosphatase, total bilirubin, albumin, prothrombin time were studied. The study indicated significant decline in reduced glutathione and total antioxidant capacity and markedly elevated levels of malondialdehyde and nitric oxide in all groups compared with the controls. Null response group had the highest levels of malondialdehyde and nitric oxide. Nitric oxide was significantly higher in those with null response compared with all other groups and with control subjects. Uric acid was significantly higher in spontaneous cure group compared with all other groups and with the controls. We concluded that CHC patients had increased oxidative stress. The oxidative status in plasma of these patients was not changed by antiviral therapy. The study also showed an important contribution of nitric oxide in null response patients. High serum uric acid did not interfere with the response and/or did not predict the response to antiviral therapy.

The effect of gabapentin on oxidative stress in a model of toxic demyelination in rat brain.

BACKGROUND: Gabapentin, a structural analog of γ-aminobutyric acid (GABA), is used in the treatment of neuropathic pain in multiple sclerosis. METHODS: This study investigated the effect of gabapentin on oxidative stress in a model of brain demyelination evoked by intracerebral injection (i.c.i) of ethidium bromide (10 µL of 0.1%). Rats received saline (control) or gabapentin at 100 or 300 mg/kg orally daily for 10 days prior to injection of ethidium bromide. Rats were euthanized 1 day later, and then the levels of reduced glutathione (GSH), glutathione peroxidase (GPx) activity, lipid peroxidation (malondialdehyde; MDA), nitrite, acetyl cholinesterase (AChE) and paraoxonase activities were assessed in the brain cortex in different treatment groups. RESULTS: Ethidium bromide resulted in increased oxidative stress in the cortex 1 day after its injection. Malondialdehyde increased by 30.2%, whereas GSH decreased by 17.6%. GPx activity was inhibited by 78.6%. Brain nitrite increased by 55.4%, AChE activity decreased by 33.4% and paraoxonase activity decreased by 27.5%. In ethidium bromide treated rats, gabapentin administered at 300 mg/kg increased cortical MDA by 66%. GSH was unaltered by gabapentin, but GPx activity decreased by 54.3% by the higher dose of gabapentin. Nitrite decreased by 21.4% and 29.2% after 100 and 300 mg/kg of gabapentin, respectively. AChE activity increased by 28.6% and 69.3% by 100 and 300 mg/kg of gabapentin, respectively. Paraoxonase activity showed 83.3% and 73% decreases by 100 and 300 mg/kg of gabapentin, respectively. CONCLUSIONS: These results suggest that gabapentin increases brain lipid peroxidation and decreases brain antioxidant enzymes in this model of chemical demyelination.

Cadmium impact and osteoporosis: mechanism of action.

CONTEXT: Cadmium (Cd) is a widespread environmental pollutant that is associated with increased risk of osteoporosis. It has been proposed that Cd's toxic effect on bone is exerted via impaired activation of vitamin D, secondary to the kidney effects. OBJECTIVE: The present study was designed to investigate the damaging impact of Cd in drinking water on bone from biochemical and histopathological point of view. MATERIALS AND METHODS: This study was conducted on 30, 3-months-old female Sprague Dawley rats exposed to cadmium chloride in a dose of 50 mg Cd/L in drinking water for 3 months. Serum was taken for determination of calcium, phosphorous levels, parathyroid hormone, 1,25 dihydroxy vitamin D(3), osteocalcin (OC) and bone specific alkaline phosphatase (BALP) activity. RESULTS: The result revealed that Cd administration induces significant increase in serum calcium (Ca), phosphorous (P) and parathyroid hormone (PTH) levels in concomitant with significant reduction in serum vitamin D(3), osteocalcin (OC) levels and bone specific alkaline phosphatase (BALP) activity. CONCLUSION: The present study provided clear evidence that long-term exposure to cadmium chloride produced marked abnormalities in bone biomarkers and increasing risk of fracture.

Neuroprotective and hepatoprotective effects of micronized purified flavonoid fraction (Daflon®) in lipopolysaccharide-treated rats.

Micronized purified flavonoid fraction (MPFF, Daflon®) is a phlebotonic drug widely used in chronic venous or lymphatic insufficiency. We aimed to investigate the effects of MPFF on hepatic and brain oxidative stress and on liver injury caused by lipopolysaccharide (LPS) in rats. MPFF (4.5, 9, or 18 mg/kg) or saline was administered orally for two days prior to intraperitoneal (i.p.) LPS (300 µg/kg) and at time of LPS administration. Rats were euthanized 4 h after LPS injection. The administration of LPS increased oxidative stress in brain and liver tissue. Malondialdehyde (MDA) increased by 193.5 and 191.8%, reduced glutathione (GSH) decreased by 73.8 and 70.8% and nitric oxide increased by 118.2 and 151.7% in the brain and liver, respectively. Serum paraoxonase 1 (PON1) activity decreased by 42.6%. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were raised by 101.8, 93.6, and 223.2%, respectively. Rats treated with MPFF at 9 and 18 mg/kg showed decreased brain MDA (27.5-34%), nitrite (25.5-41%) and increased GSH (27.2-74.1%). In the liver, MDA decreased by 16.4-59.8%, nitrite decreased by 54.7-56.7%, and GSH increased by 15.2-70.5% with MPFF at 4.5, 9, or 18 mg/kg, respectively. Serum PON1 activity showed 41-65.9% increments with MPFF. Significant reductions in serum AST, ALT, and ALP were seen after treatment with MPFF. Moreover, the degree of histological damage, expression of the inducible form of nitric oxide synthase and the apoptotic enzyme caspase-3 in the liver were substantially reduced. MPFF thus prevented the increased oxidative stress and inflammation in brain and liver as well as the liver dysfunction caused by endotoxemia in the rat.

Neuroprotective effect of nitric oxide donor isosorbide-dinitrate against oxidative stress induced by ethidium bromide in rat brain.

This study investigated the effect of systemic administration of isosorbide-dinitrate (ISDN) on oxidative stress and brain monoamines in a toxic model of brain demyelination evoked by intracerebral injection (i.c.i) of ethidium bromide (10 µl of 0.1 %). Rats received saline (control) or ISDN at 5 or 10 mg/kg for 10 days prior to injection of ethidium bromide. Rats were euthanized one day later, and then the levels of reduced glutathione (GSH), lipid peroxidation (malondialdehyde; MDA), nitric oxide (nitrite/nitrate), acetylcholinesterase (AChE) activity, paraoxonase activity as well as monoamine levels (serotonin, dopamine and noradrenaline) were assessed in the brain cortex in different treatment groups. The i.c.i of ethidium bromide resulted in increased oxidative stress in the cortex one day after its injection; (i) MDA increased by 36.9 %; (ii) GSH decreased by 20.8 %, while (iii) nitric oxide increased by 60.3 %; (iv) AChE and paraoxonase activities in cortex decreased by 35.9 % and 29.4 %, respectively; (v) serotonin was significantly increased. In ethidium bromide-treated rats, pretreatment with ISDN at 10 mg/kg decreased cortical MDA by 23.9 %. Reduced glutathione was increased by 25.1 % ISDN at 10 mg/kg, while nitric oxide showed a 32.8 and 41.7 % decrease after 5 and 10 mg/kg of ISDN, respectively. Acetylcholinesterase activity increased by 24.3 % by 10 mg/kg of ISDN. Paraoxonase activity showed further decrease by 72.2 and 83.8 % after treatment with 5 and 10 mg/kg of ISDN, respectively. The administration of ISDN decreased the level of serotonin and noradrenaline compared with the ethidium bromide only treated group. Overall, the present findings suggest neuroprotective effect of ISDN against oxidative stress in this model of chemical demyelination.

The effects of trimetazidine on lipopolysaccharide-induced oxidative stress in mice.

The effects of trimetazidine, a novel anti-ischemic agent, on the development of oxidative stress induced in mice with lipopolysaccharide endotoxin were investigated. The drug was administered orally once daily at doses of 1.8, 3.6 or 7.2 mg/kg for two days prior to intraperitoneal (i.p.) injection of lipopolysaccharide E (200 µg/kg) and at time of endotoxin administration. Mice were euthanized 4 h after administration of the lipopolysaccharide. Lipid peroxidation (malondialdehyde; MDA), reduced glutathione (GSH) and nitric oxide (nitrite/nitrate) concentrations were measured in brain and liver. The administration of lipopolysaccharide increased oxidative stress in both the brain and liver tissue. MDA increased by 33.9 and 107.1 %, GSH decreased by 23.9 and 84.3 % and nitric oxide increased 70.3 and 48.4 % in the brain and liver, respectively. Compared with the lipopolysaccharide control group, brain MDA decreased by 26.2 and 36.7 %, while GSH increased by 18.2 and 25.8 % after the administration of trimetazidine at 3.6 and 7.2 mg/kg, respectively. Brain nitric oxide decreased by 45.3, 50.8 and 57.0 % by trimetazidine at 1.8, 3.6 and 7.2 mg/kg, respectively. In the liver, MDA decreased by 18.7, 30.7 and 49.4 % and GSH increased by 150.3, 204.8 and 335.4 % following trimetazidine administration at 1.8, 3.6 and 7.2 mg/kg. Meanwhile, nitric oxide decreased by 17.3 % by 7.2 mg/kg of trimetazidine. These results indicate that administration of trimetazidine in the presence of mild systemic inflammatory response alleviates oxidative stress in the brain and liver.