Prolactin and blood-brain barrier permeability.

Area of Science:

• Neuroscience
• Endocrinology
• Cell Biology

Background:

• The blood-brain barrier (BBB) is crucial for brain homeostasis, regulating substance transport via endothelial tight junctions (TJs).
• Prolactin (PRL) influences endothelial cells, but its specific role in BBB permeability remains unclear.

Purpose of the Study:

• To investigate the effects of prolactin (PRL) on blood-brain barrier (BBB) permeability and endothelial cell function.
• To elucidate the molecular mechanisms underlying PRL's influence on BBB integrity.

Main Methods:

• Primary bovine brain microvessel endothelial cells were cultured as an in vitro BBB model.
• Cells were treated with varying concentrations of PRL (0.1–100 nM) for 24 hours.
• Assays included proliferation, apoptosis, nitric oxide (NO) production, permeability, trans-endothelial electrical resistance (TEER), and TJ protein expression (claudin-5, occludin).

Main Results:

• PRL significantly increased endothelial cell proliferation at 10 and 100 nM, mediated by nitric oxide (NO).
• PRL decreased BBB permeability and increased TEER independently of NO.
• PRL upregulated the expression of tight junction proteins claudin-5 and occludin.

Conclusions:

• Prolactin enhances BBB integrity by promoting endothelial cell proliferation and increasing tight junction protein expression.
• PRL reduces BBB permeability, suggesting a role in regulating brain endothelial cell function and barrier properties.