The Function And Mechanism Of Vrac Channels In Ischemic Brain Damage In Rats

Purpose Establish cerebral ischemia reperfusion model in rats. Compared the nerve behavioral score, pathological features of H-E staining and Nissl staining, caspase-3 immunofluorescence staining for marking the apoptosis of cortical neurons after the application of inhibitors of volume-regulated anion channel, such as TAM, NPPB, DCPIB. Studying the function and mechanism of volume-regulated anion channel in ischemia neuronal injury in rats, so as to provide a new theoretical basis for the clinical treatment of ischemic nerve injury.Methods The middle cerebral artery occlusion (MCAO) model was made by suture, as to induce focal cerebral ischemia for 2 hours and then reperfusion. All rats were divided into sham group, MCAO+inhibitor group and MCAO+DMSO group, and the MCAO+inhibitor group including the TAM group, NPPB group, DCPIB group. Stereotactic injection of VRAC inhibitors TAM, NPPB, DCPIB and DMSO into the ventricle was applicated immediately after cerebral ischemia in MCAO+inhibitor group and MCAO+DMSO group. The nerve behavioral score was first achieved 24 hours after the establishment of MCAO model and then scored everyday. All models were decapitated at different time points 24 hours, 3 days, 3 weeks. The brain tissues were taken for pathological examination and Nissl staining, caspase-3 immunofluorescence staining for marking the apoptosis of cortical neurons. Results The nerve behavioral score of MCAO+inhibitor group is higher than the MCAO+DMSO group, P < 0.05. The number of apoptotic neurons in MCAO+inhibitor group marked by Nissl staining, caspase-3 immunofluorescence staining decreased compared with MCAO+DMSO group. H-E staining showed that MCAO+inhibitor group: neurons, hippocampal pyramidal cells, glial cells and capillaries were in normal shape, structural integrity, the nucleolus is clear and the cytoplasm is pure without red dye. MCAO+DMSO group: the size of neurons reduced significantly, staining deepening, cytoplasm and nuclear condensation, dendrite disappeared. There are large number of sieve-like necrosis with many glial cells, and the interstitial edema is obvious.Conclusions 1.After the application of VRAC inhibitors,the deficits of nerve behavior were improved significantly.2.VRAC channels may play a protective role in ischemic neuronal injury by reducing the neuronal apoptosis, so as to provide a new theoretical basis for the clinical treatment of ischemic nerve injury.