6-Hydroxydopamine-induced alterations in blood-brain barrier permeability

Area of Science:

• Neuroscience
• Neuroinflammation
• Neuropharmacology

Background:

• Vascular inflammation is known to impair blood-brain barrier (BBB) function.
• The impact of parenchymal inflammation, such as in Parkinson's disease models, on BBB integrity is not well understood.

Purpose of the Study:

• To investigate whether dopamine (DA) neuron lesions compromise BBB function.
• To explore the consequences of BBB disruption in a Parkinson's disease model.

Main Methods:

• Assessed BBB integrity using FITC-albumin and horseradish peroxidase leakage in 6-hydroxydopamine (6OHDA) lesioned animals.
• Examined microglial activation, DA neuron loss, and protein expression (P-glycoprotein, beta 3-integrin).
• Evaluated drug permeability across the BBB using domperidone and apomorphine in behavioral studies.

Main Results:

• 6OHDA lesions led to increased BBB leakage in the substantia nigra and striatum.
• Lesions caused microglial activation and DA neuron reduction.
• BBB leakage correlated with increased P-glycoprotein and beta 3-integrin expression.
• Domperidone crossed the BBB in lesioned animals, suggesting impaired barrier function.

Conclusions:

• Dopamine neuron loss associated with Parkinson's-like pathology compromises blood-brain barrier integrity.
• BBB disruption may allow normally excluded substances to enter the brain, impacting drug efficacy.
• These findings highlight a potential mechanism linking neurodegeneration and altered brain pharmacokinetics.