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Effects of Selegiline in a retroviral rat model for neurodegenerative disease
1Institut für Virologie, Universität Wurzburg, Germany.
Abstract:
Upon inoculation into neonatal rats, murine leukemia virus (MuLV) NT40 causes a non-inflammatory degeneration of the central nervous system. While microglia cells appear to be the major target cells within the brain parenchyma for neurovirulent MuLV, degenerating neurons do not express retroviral gene products. In order to protect rats from neuronal damage we treated retrovirally infected rats once with monoamine oxidase (MAO) B inhibitor Selegiline which--under different conditions--exerts neuroprotective effects. Unexpectedly, when administered at 17 days post-infection (d.p.i.) a single intraperitoneal dose of Selegilin (1 mg/kg bodyweight) significantly shortened the incubation period for neurological disease. In contrast, Selegiline given in a lower dosage (0.05 mg/kg bodyweight) and/or at a different time point (13 d.p.i.) at the low (0.05 mg/kg bodyweight) and the high dose (1.0 mg/kg bodyweight) had no effect on the outcome of neurological disease. Animals treated with Selegiline (1.0 mg/kg bodyweight at 17 d.p.i.) contained higher amounts of viral loads in the CNS, higher numbers of brain cells expressing major histocompatibility complex class II molecules, and exhibited inhibition of MAO-B in comparison to untreated yet infected (control) animals. Supposedly, Selegiline activated the major target cell population of the CNS for MuLV-NT40, microglia, with the consequence of enhanced susceptibility for retroviral infection and triggered endogenous mechanism(s) involved in the pathogenesis of retroviral neurodegeneration.
Insights
Monoamine oxidase B inhibitor Selegiline unexpectedly accelerated neurological disease in rats infected with murine leukemia virus (MuLV) NT40. This occurred when administered at 17 days post-infection, suggesting Selegiline activates microglia, enhancing viral susceptibility and neurodegeneration.
Area of Science:
- Neurovirology
- Neuroimmunology
- Pharmacology
Background:
- Murine leukemia virus (MuLV) NT40 causes non-inflammatory central nervous system (CNS) degeneration in neonatal rats.
- Microglia are the primary target cells in the brain parenchyma for neurovirulent MuLV, though neurons do not express retroviral gene products.
- Monoamine oxidase (MAO) B inhibitor Selegiline is known to exert neuroprotective effects under certain conditions.
Purpose of the Study:
- To investigate the potential neuroprotective effects of Selegiline against MuLV-NT40-induced neurodegeneration in rats.
- To determine if Selegiline administration can prevent or mitigate neuronal damage in retrovirally infected rats.
Main Methods:
- Neonatal rats were infected with MuLV-NT40.
- Infected rats were treated with a single intraperitoneal dose of Selegiline at different time points (13 and 17 days post-infection) and dosages (0.05 mg/kg and 1.0 mg/kg).
- Viral loads in the CNS, expression of major histocompatibility complex class II molecules in brain cells, and MAO-B activity were assessed.
Main Results:
- A single high dose (1.0 mg/kg) of Selegiline administered at 17 days post-infection significantly shortened the incubation period for neurological disease.
- Lower doses (0.05 mg/kg) and/or administration at an earlier time point (13 days post-infection) had no significant effect on disease outcome.
- Animals receiving the high-dose, late Selegiline treatment showed increased viral loads in the CNS, more cells expressing MHC class II, and inhibited MAO-B activity compared to controls.
Conclusions:
- Unexpectedly, Selegiline administration at a specific time point (17 d.p.i.) and dose (1.0 mg/kg) exacerbated MuLV-NT40 neurodegeneration in rats.
- The findings suggest Selegiline may activate microglia, the primary target cells for MuLV-NT40, leading to enhanced retroviral susceptibility and triggering endogenous mechanisms of neurodegeneration.
- These results highlight a complex interaction between Selegiline, microglia, and retroviral pathogenesis in the CNS.