Novel neuroprotective and hepatoprorective 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(ACh E) 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(i NOS) 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 ACh E increased but PON1 and butyrylcholinesterase activities decreased by citric acid. Liver enzymes, the percentage of damaged blood lymphocytes, histopathological alterations and i NOS 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, ACh E and glucose. The drug also decreased DNA damage of peripheral blood lymphocytes, histopathological alterations and i NOS 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.

Neuroprotection by misoprostol against rotenone-induced neurotoxicity in rat brain

Objective: To investigate the effect of the prostaglandin E1 analogue misoprostol on oxidative stress and neurodegeration caused by subcutaneous rotenone administration in rats. Methods:Rotenone was administered in a dose of 1.5 mg/kg every other day for 2 weeks. Starting from the 1 st day of rotenone injection, rats were subcutaneously treated with misoprostol at doses of10, 100 or 1 000 μg/kg. Rats were evaluated for brain lipid peroxidation(malondialdehyde:MDA), reduced glutathione(GSH), nitric oxide(NO) levels, and paraoxonase-1(PON-1) activity.The concentrations of the anti-apoptotic protein B cell/lymphoma-2(Bcl-2) were determined in the striatum. Histopathologic examination and the expression of inducible nitric oxide synthase(iNOS) in the cerebral cortex and striatum were also performed. Results: Compared with the vehicle-treated group, rotenone caused a significant increase in brain lipid proxidation(MDA)by 61%(P<0.05) accompanied by an increase in NO by 73.1%(P<0.05) and a decrease in GSH concentration by 29.4%(P<0.05). In addition, brain PON-1 activity significantly decreased by63.0%(P<0.05) and striatal Bcl-2 significantly decreased by 27.9%(P<0.05) with respect to the corresponding control value. Brain sections from rotenone treated rats showed extensive dark pyknotic and apoptotic nuclei in neurons, shrunken cytoplasm and perineuronal vacuolation.Rotenone also caused pronounced expression of iNOS in the cerebral cortex and striatum.Treatment with misoprostol at doses of 100 and 1 000 μg/kg resulted in decreased brain MDA(by 16.5%-23.0%)(P<0.05) and NO levels(by 37.1%-40.7%)(P<0.05) and increased GSH concentrations(by 18.8%-30.1%)(P<0.05). PON-1 activity was significantly increased by80.0%-114.8%(P<0.05) by misoprostol at 100 and 1 000 μg/kg, respectively. In addition,misoprostol treatment restored striatal Bcl-2 concentrations to its normal value. Misoprostol treatment resulted in markedly reduced brain injury and decreased iNOS expression in the cerebral cortex and striatum of rotenone intoxicated rats. Conclusions: These data suggest that misoprostol prevents the rotenone-induced neurodegeneration in rat brain by reducing brain oxidative stress.

Preventive effects of cannabis on neurotoxic and hepatotoxic activities of malathion in rat

Objective: To investigate the effect of Cannabis sativa extract on the development of neuroand hepato-toxicity caused by malathion injection in rats. Methods: The extract of Cannabis sativa was obtained from the plant resin by chloroform treatment. Δ~9-Tetrahydrocannabinol content of the extract(20%) was quantified using gas chromatography–mass spectrometry. The doses of cannabis extract were expressed as Δ~9-tetrahydrocannabinol content of 10 or 20 mg/kg. Malathion(150 mg/kg) was intraperitoneally administered followed after 30 min by the cannabis extract(10 or 20 mg/kg, subcutaneously). Rats were euthanized 4 h later. Malondialdehyde(MDA), reduced glutathione(GSH), nitric oxide and paraoxonase-1(PON-1) activity were determined in brain and liver. Brain 5-lipoxygenase and butyrylcholinesterase(BChE) activity were measured as well. Histopathological examination of brain and liver tissue was also performed. Results: Compared to controls, malathion resulted in increased oxidative stress in brain and liver. MDA and nitric oxide concentrations were significantly increased(P<0.05) and GSH significantly decreased with respect to control levels(P<0.05). Malathion also significantly inhibited PON-1 and BChE activities but had no effect on brain 5-lipoxygenase. Brain MDA concentrations were not altered by cannabis treatment. Cannabis at 20 mg/kg, however, caused significant increase in nitric oxide and restored the GSH and PON-1 activity. Brain BChE activity significantly decreased by 26.1%(P<0.05) after treatment with 10 mg/kg cannabis. Cannabis showed no effect on brain 5-lipoxygenase. On the other hand, rats treated with cannabis exhibited significantly higher levels of liver MDA, nitric oxide and PON-1 activity compared with the malathion control group. Rats treated with only malathion exhibited spongiform changes, neuronal damage in the cerebral cortex and degeneration of some Purkinje cells in the cerebellum. There were also hepatic vacuolar degeneration and dilated and congested portal vein. These histopthological changes induced by malathion in brain and liver were reduced to great extent by cannabis administration at 20 mg/kg. Conclusions: Our data suggest that acute treatment with cannabis alleviates the malathion-induced brain and hepatic injury in rats possibly by maintaining the levels of GSH and PON-1 activity.

Acetylcholinesterase,butyrylcholinesterase and paraoxonase 1 activities in rats treated with cannabis,tramadol or both

Objective:To investigate the effect of Cannabis sativa resin and/or tramadol,two commonly drugs of abuse on acetylcholinesterase and butyrylcholinesterase activities as a possible cholinergic biomarkers of neurotoxicity induced by these agents.Methods:rats were treated with cannabis resin(5,10 or 20 mg/kg)(equivalent to the active constituent A'-tetrahydrocannabinol),tramadol(5,10 and 20 mg/kg) or tramadol(10 mg/kg)combined with cannabis resin(5,10 and 20 mg/kg) subcutaneously daily for 6 weeks.Acetylcholinesterase(AChE) and butyrylcholinesterase(BChE) activities were measured in brain and serum.We also measured the activity of paraoxonase-1(PONl) in serum of rats treated with these agents.Results:(i) AChE activity in brain increased after 10-20 mg/kg cannabis resin(by 16.3%-36.5%).AChE activity in brain did not change after treatment with 5-20 mg/kg tramadol.The administration of both cannabis resin(5,10 or 20 mg/kg) and tramadol(10 mg/kg) resulted in decreased brain AChE activity by 14.1%,12.9%and 13.6%,respectively;(ii) BChE activity in serum was markedly and dose-dependenlly inhibited by cannabis resin(by 60.9%-76.9%).BChE activity also decreased by 17.6%-36.5%by 10-20mg/kg tramadol and by 57.2%-63.9%by the cannabis resin/tramadol combined treatment;(iii)Cannabis resin at dose of 20 mg/kg increased serum PONl activity by 25.7%.In contrast,tramadol given at 5,10 and 20 mg/kg resulted in a dose-dependent decrease in serum PON1 activity by 19%,36.7%,and 46.1%,respectively.Meanwhile,treatment with cannabis resin plus tramadol resulted in 40.2%,35.8%,30.7%inhibition of PONl activity compared to the saline group.Conclusions:these data suggest that cannabis resin exerts different effects on AChE and BChE activities which could contribute to the memory problems and the decline in cognitive function in chronic users.

Bougainvillea spectabilis flowers extract protects against the rotenone-induced toxicity

Objective:To investigate the effect of two extracts of Bougainvillea spectabilis(B. spectabilis) flowers with yellow and pink/purple on brain oxidative stress and neuronal damage caused in rats by systemic rotenone injection. Methods:Rotenone 1.5 mg/kg was given three times per week alone or in combination with B. spectabilis flowers extracts(25 mg or 50 mg) via the subcutaneous route for 2 weeks. Brain concentrations of the lipid peroxidation marker malondialdehyde(MDA),reduced glutathione,nitric oxide(nitrite),the pro-inflammatory cytokine interleukin-1beta(Il-1β) as well as butyrylcholinesterase,and paraoxonase-1(PON-1) activities,were determined. Histopathology and caspase-3 immunohistochemistry were also performed. Results:Rotenone resulted in significant increases of brain MDA(the product of lipid peroxidation),and nitric oxide content along with decreased brain reduced glutathione. There were also marked and significant inhibition of brain PON-1 and BCh E activities and increased Il-1β in brain of rotenone-treated rats. B. spectabilis flowers extract itself resulted in brain oxidative stress increasing both lipid peroxidation and nitrite content whilst inhibiting PON-1 activity. The yellow flowers extract inhibited BCh E activity and increased brain Il-1β. When given to rotenone-treated rats,B. spectabilis extracts,however,decreased lipid peroxidation while their low administered doses increased brain GSH. Brain nitrite decreased by the pink extract but showed further increase by the yellow extract. Either extract,however,caused further inhibition of PON-1 activity while the yellow extract resulted in further inhibition of BChE activity. Histopathological studies indicated that both extracts protected against brain,liver and kidney damage caused by the toxicant. Conclusions:These data indicate that B. spectabilis flowers extracts exert protective effect against the toxic effects of rotenone on brain,liver and kidney. B. spectabilis flowers extracts decreased brain lipid peroxidation and prevented neuronal death due to rotenone and might thus prove the value in treatment of Parkinson's disease.