title: Ginkgo biloba affords dose-dependent protection against 6-hydroxydopamine-induced parkinsonism in rats: neurobehavioural, neurochemical and immunohistochemical evidences.
abstract: Ginkgo biloba extract (EGb), a potent antioxidant and monoamine oxidase B (MAO-B) inhibitor, was evaluated for its anti-parkinsonian effects in a 6-hydroxydopamine (6-OHDA) rat model of the disease. Rats were treated with 50, 100, and 150 mg/kg EGb for 3 weeks. On day 21, 2 microL 6-OHDA (10 microg in 0.1% ascorbic acid saline) was injected into the right striatum, while the sham-operated group received 2 microL of vehicle. Three weeks after 6-OHDA injection, rats were tested for rotational behaviour, locomotor activity, and muscular coordination. After 6 weeks, they were killed to estimate the generation of thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) content, to measure activities of glutathione-S-transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD), and to quantify catecholamines, dopamine (DA) D2 receptor binding, and tyrosine hydroxylase-immunoreactive (TH-IR) fibre density. The increase in drug-induced rotations and deficits in locomotor activity and muscular coordination due to 6-OHDA injections were significantly and dose-dependently restored by EGb. The lesion was followed by an increased generation of TBARS and significant depletion of GSH content in substantia nigra, which was gradually restored with EGb treatment. EGb also dose-dependently restored the activities of glutathione-dependent enzymes, catalase, and SOD in striatum, which had reduced significantly by lesioning. A significant decrease in the level of DA and its metabolites and an increase in the number of dopaminergic D2 receptors in striatum were observed after 6-OHDA injection, both of which were significantly recovered following EGb treatment. Finally, all of these results were exhibited by an increase in the density of TH-IR fibers in the ipsilateral substantia nigra of the lesioned group following treatment with EGb; the lesioning had induced almost a complete loss of TH-IR fibers. Considering our behavioural studies, biochemical analysis, and immunohistochemical observation, we conclude that EGb can be used as a therapeutic approach to check the neuronal loss following parkinsonism.
authors.affiliation: Neurotoxicology Laboratory, Department of Medical Elementology & Toxicology, Jamia Hamdard (Hamdard University), Hamdard Nagar; New Delhi, India. mahmad7@jhmi.edu
authors.forename: Muzamil
authors.initials: M
authors.lastname: Ahmad
authors.forename: Sofiyan
authors.initials: S
authors.lastname: Saleem
authors.forename: Abdullah Shafique
authors.initials: AS
authors.lastname: Ahmad
authors.forename: Seema
authors.initials: S
authors.lastname: Yousuf
authors.forename: Mubeen Ahmad
authors.initials: MA
authors.lastname: Ansari
authors.forename: M Badruzzaman
authors.initials: MB
authors.lastname: Khan
authors.forename: Tauheed
authors.initials: T
authors.lastname: Ishrat
authors.forename: Rajnish Kumar
authors.initials: RK
authors.lastname: Chaturvedi
authors.forename: Ashok Kumar
authors.initials: AK
authors.lastname: Agrawal
authors.forename: Fakhrul
authors.initials: F
authors.lastname: Islam
mesh_terms: D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects*; D001923:Brain Chemistry / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D004195:Disease Models, Animal; D018491:Dopamine Agonists / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D020441:Ginkgo biloba / Q000737:chemistry*; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D016627:Oxidopamine; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000378:metabolism* / Q000517:prevention & control*; D010936:Plant Extracts / Q000627:therapeutic use; D011597:Psychomotor Performance / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D013239:Stereotyped Behavior / Q000187:drug effects; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D002395:Catecholamines; D018491:Dopamine Agonists; D018765:Dopamine Uptake Inhibitors; D010936:Plant Extracts; D017448:Receptors, Dopamine D2; D017392:Thiobarbituric Acid Reactive Substances; D016627:Oxidopamine; D000661:Amphetamine; D005979:Glutathione Peroxidase; D014446:Tyrosine 3-Monooxygenase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005978:Glutathione; D001058:Apomorphine