TIGHT JUNCTIONS PROTEINS IN CEREBRAL ENDOTHELIAL CELLS DURING EARLY POSTNATAL DEVELOPMENT

Area of Science:

• Neuroscience
• Developmental Biology
• Physiology

Background:

• The blood-brain barrier (BBB) is crucial for brain development and function.
• Its formation and plasticity involve molecular events in the brain neurovascular unit.
• Understanding BBB development under physiological and stress conditions is vital.

Purpose of the Study:

• To investigate the expression of tight junction proteins (JAM, ZO1, CLDN5) in the developing rat brain.
• To characterize blood-brain barrier genesis under physiological conditions.
• To examine the impact of perinatal hypoxia and early life stress on BBB development.

Main Methods:

• Examined protein expression of cerebral endothelial tight junctions (JAM, ZO1, CLDN5).
• Studied rats at postnatal days 7, 28, and 70 (P7–P70).
• Assessed expression changes under physiological, hypoxic, and early stress conditions.

Main Results:

• Physiological conditions showed a slight increase in JAM, ZO1, and CLDN5 expression from P7 to P70.
• Perinatal hypoxia increased JAM and CLDN5 expression but decreased ZO1 expression by P28–P70.
• Early life stress caused an imbalance in ZO1 and tight junction protein expression, opposite to hypoxia.

Conclusions:

• BBB tight junction protein expression changes during postnatal development.
• Perinatal hypoxia and early life stress significantly alter BBB development and protein expression.
• These findings highlight the vulnerability of the developing BBB to early-life insults.