Mechanism of the protective effect of progesterone on blood brain barrier in rats with cerebral infarction

Objective To investigate the inhibitory effects of progesterone on the inflammatory response and its influence on the structure of the blood brain barrier (BBB) of rats after cerebral infarction. Methods Progesterone was injected intrapefitoneally following permanent middle cerebral artery occlusion (MCAO) in rats. Western blotting was used to detect the expressions of tumor necrosis factor-alpha (TNF-α) and claudin-5, the major component of tight-junction proteins associated with the BBB. The water content in the injured brain tissue was also examined. Results The expression level of TNF-α increased but claudin-5 expression decreased in the brain tissue of all the rats following MCAO. Progesterone treatment significantly reduced the TNF-α expression in comparison with the vehicle-treated rats, resulting also in ameliorated claudin-5 protein loss and reduced water content in the injured brain tissue. Conclusion Progesterone inhibits the inflammatory response and mitigates the brain damage after cerebral infarction in rats, suggesting the role of this steroid as a neuroprotective agent. Key words: Progesterone; Cerebral infarction; Tumor necrosis factor-α; Blood-brain barrier