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Chronic administration of malonic acid produces selective neural degeneration and transient changes in calbindin
T J Bazzett1, R C Falik, J B Becker
1Department of Neurology, University of Michigan, Ann Arbor 48104-1687, USA.
Abstract:
Adult rats received chronic dialytic delivery devices that exposed the striatum to a 100 mM, 400 mM, or 4 M solution of the reversible succinate dehydrogenase inhibitor malonic acid (MA). Three weeks of exposure to 100 or 400 mM MA produced no significant reduction in striatal cytochrome oxidase staining, whereas striata chronically exposed to 1 and 4 M MA showed a significant and dose-related reduction in cytochrome oxidase staining. In striata exposed to 1 M MA, analysis of regions radial to the necrotic core revealed significant reduction of nissl cell staining with relative sparing of NADPH-diaphorase-containing neurons. Although 100 and 400 mM MA failed to produce lesions, both of these concentrations significantly decreased the number of striatal calbindin (CALB) immunoreactive perikarya. The reduction in CALB immunoreactivity was partly reversed in animals allowed to survive 4 weeks after cessation of exposure to 400 mM MA. These results indicate that, like striatal lesions produced by quinolinic acid, lesions produced by chronic exposure to MA possess a Huntington's disease-like pattern of selective neurodegeneration. In addition, exposure to subthreshold MA concentrations (100 and 400 mM) produce widespread transient changes in striatal CALB that may be associated with a premorbid state of neuronal dysfunction.
Insights
Malonic acid (MA) exposure in rats caused dose-dependent striatal damage, mimicking Huntington's disease neurodegeneration. Lower MA concentrations induced transient changes in calbindin, suggesting a premorbid state.
Area of Science:
- Neuroscience
- Neurotoxicology
- Cellular Biology
Background:
- Huntington's disease (HD) is a neurodegenerative disorder characterized by selective striatal neuron loss.
- Succinate dehydrogenase inhibitors, like malonic acid (MA), are implicated in neurotoxicity.
- Understanding MA's neurotoxic effects can elucidate HD pathogenesis.
Purpose of the Study:
- To investigate the neurotoxic effects of chronic malonic acid (MA) exposure on the rat striatum.
- To determine if MA-induced striatal lesions exhibit a pattern similar to Huntington's disease.
- To examine the impact of sub-lesional MA concentrations on neuronal markers.
Main Methods:
- Adult rats received chronic striatal exposure to varying concentrations of malonic acid (MA) via dialytic delivery.
- Assessed striatal damage using cytochrome oxidase and Nissl staining.
- Quantified NADPH-diaphorase and calbindin (CALB) immunoreactivity in affected striatal regions.
Main Results:
- Chronic exposure to 1 M and 4 M MA caused significant, dose-related reductions in cytochrome oxidase staining.
- 1 M MA exposure led to reduced Nissl staining, with relative sparing of NADPH-diaphorase neurons.
- Sub-lesional MA concentrations (100 and 400 mM) decreased calbindin (CALB) immunoreactivity, which showed partial reversal upon MA cessation.
Conclusions:
- MA-induced striatal lesions in rats exhibit a pattern of selective neurodegeneration resembling Huntington's disease.
- Transient changes in striatal calbindin (CALB) at sub-lesional MA concentrations may indicate a premorbid state of neuronal dysfunction.