Mechanisms of dexmedetomidine-induced cerebral protection following ischemic brain injury via the brain-derived neurotrophic factor–tyrosine kinase receptor B pathway

OBJECTIVE: To investigate the protective effects of dexmedetomidine on cerebral ischemia-reperfusion injury through the activation of the brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TrkB) signaling pathway. METHODS: This study utilized hippocampal neuronal oxygen-glucose deprivation/reoxygenation (OGD/R) models and rat middle cerebral artery occlusion models, with dexmedetomidine intervention. RESULTS: Compared with the sham-operated group, the model group rats exhibited a significant increase in Zea-Longa scores, a marked prolongation of the escape latency, a notable reduction in the number of platform crossings, a significant increase in the percentage of cerebral infarct size, and a marked decrease in the expression of BDNF, TrkB, and Bcl-2 proteins and mRNA ( P < 0.05). The dexmedetomidine group showed significantly better outcomes in all above parameters compared to the model group. Compared with the control group, the OGD/R group exhibited a reduction in hippocampal neuronal cell viability, a significant increase in apoptosis rate, elevated expression of Bax and C-caspase-3 proteins, a marked decrease in Bcl-2 protein levels, and a significant reduction in the expression of BDNF and TrkB proteins and mRNA ( P < 0.05). CONCLUSION: Dexmedetomidine exerts significant neuroprotective effects by activating the BDNF/TrkB signaling pathway, thereby alleviating ischemic brain injury.