Initiating TrkB/Akt Signaling Cascade Preserves Blood–Brain Barrier after Subarachnoid Hemorrhage in Rats

The integrity of the blood–brain barrier (BBB) plays a vital role in affecting the prognosis of subarachnoid hemorrhage (SAH). This study aimed to investigate activation of the Tropomyosin-related kinase receptor B (TrkB) and its downstream signaling pathway on preserving BBB breakdown after experimental SAH. An endovascular perforation SAH model was applied. N-[2-(5-hydroxy-1H-indol-3-yl) ethyl]-2- oxopiperidine-3-carboxamide (HIOC), the derivative of N-acetyl serotonin (NAS), was intracerebroventricularly administered 3 h after SAH induction. The neurologic scores and brain water content were evaluated in an outcome study. Western blot and immunofluorescence staining were used to investigate the mechanism. The results indicated that HIOC activated the TrkB/Akt pathway, increased the tight junction expression, improved neurologic deficits, and ameliorated brain edema after SAH. Thus, we conclude that initiating the TrkB/Akt signaling cascade preserves BBB breakdown after experimental SAH in rats.