increased expression of tight junction proteins and blood-brain barrier integrity in mcao rats following injection of mir-149-5p

Cerebral ischemia is a common neurodegenerative disease in which damage to the blood-brain barrier (bbb) is the main consequence. in cerebral ischemia, the level of mir-149-5p and tight junction proteins are decreased, while the level of calpine is increased, finally leading to increased bbb permeability. this study investigated the effect of mir-149-5p mimic on the expression of calpain, occludin, and zo-1 and the consequences of cerebral ischemia. cerebral ischemia model was performed via middle cerebral artery occlusion (mcao) method on female wistar rats. four groups of wistar rats were studied: sham, cerebral ischemia without treatment, scramble mir, and mir-149-5p mimic treatment. then, neurological defects and bbb permeability (via evans blue staining), cerebral edema (cerebrospinal fluid percentage), and zo-1, occludin, and calapin expression (by quantitative real time- pcr) were investigated. qrt-pcr results showed mir-149-5p expression decreases after cerebral ischemia induction. in addition, occludin and zo-1 expression significantly increased in mir-149-5p group. in contrast, calapin expression, bbb permeability, brain water content and neurological defects were significantly decreased. it seems that the increased level of mir-149-5p exerts its protective effect on cerebral ischemia due to increasing of tight junction proteins.