Acute versus long-term effects of 6-hydroxydopamine on oxidative stress and dopamine depletion in the striatum of mice

• Published in: Journal of neuroscience methods 2011-11, Vol.202 (2), p.128-136
• Main Authors: Varcin, Mustafa, Bentea, Eduard, Mertens, Birgit, Van Den Haute, Chris, Baekelandt, Veerle, Michotte, Yvette, Sarre, Sophie
• Format: Article
• Language: English
• Subjects: 6-Hydroxydopamine; Acute Disease; Animals; Chronic Disease; Corpus Striatum - drug effects; Corpus Striatum - metabolism; Corpus Striatum - physiopathology; Dopamine - deficiency; Dopamine - secretion; Female; Mice; Mice, Inbred C57BL; Microdialysis; Microdialysis - methods; Neurotoxins - toxicity; Oxidative stress; Oxidative Stress - drug effects; Oxidative Stress - physiology; Oxidopamine - toxicity; Parkinsonian Disorders - metabolism; Parkinsonian Disorders - physiopathology; Salicylate trapping; Striatum; Time
• ISSN: 0165-0270; 1872-678X
• DOI: 10.1016/j.jneumeth.2011.07.004

► Measurement of 6-OHDA induced hydroxyl radical formation in mouse striatum in vivo. ► Measurement of acute and long-term effects of induced 6-OHDA oxidative stress. ► Detecting differences in the degree of 6-OHDA induced hydroxyl radical formation. ► Applicable method in mouse models of Parkinson's disease, including transgenic mice models. Oxidative stress is one of the mechanisms which may be important in the pathogenesis of Parkinson's disease. In the current study, the effects of 6-hydroxydopamine (6-OHDA) perfusion on hydroxyl radical formation in the mouse striatum were investigated using the in vivo salicylate trapping microdialysis technique. The latter uses salicylate as a trapping agent for hydroxyl radicals with formation of 2,3-dihydroxybenzoic acid (2,3-DHBA), which is measured by HPLC. Two different approaches of the technique were validated in mice. First, perfusion of the trapping agent salicylate (1 mM) via the probe in combination with 6-OHDA (5 μM) was used to screen for radical scavenging properties of compounds in mice. Alternatively, striatal administration of 6-OHDA in a concentration known to induce nigrostriatal denervation (1 mM), without the trapping agent, allowed to maximally challenge the neuronal microenvironment and as such to investigate both its acute and long-term effects. In the first method, as expected, glutathione (GSH) (1.5 mM) prevented the 6-OHDA-induced increase in 2,3-DHBA levels. In the second method, GSH prevented the hydroxyl radical formation, while depletion of GSH with 2-cyclohexen-1-one (CHO) resulted in significantly higher 2,3-DHBA levels than when 6-OHDA was perfused alone. Three weeks after the local 6-OHDA perfusion, the total striatal dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) content were reduced by 30%, compared to the intact striatum, accompanied by a reduction in striatal tyrosine hydroxylase (TH) immunoreactive (ir) nerve terminals. This suggests that the second method can be used to determine the acute as well as the long-term effects of 6-OHDA in the mouse striatum.