Protective Effects Of The Phenolic Component From Gastrodia Elata Blume.on The Neurovascular Unit

Objective:Cerebral ischemia reperfusion injury(CIRI)is an important cause of ischemic stroke(IS)deterioration.Considering the complex mechanism involved in the pathological process of CIRI,most drugs only act on a single target.The neurovascular unit(NVU)was proposed as a structural and functional unit in an integrated model.The NVU unites neuronal activity and vascular function,controls brain homeostasis,and maintains an optimal brain microenvironment by adjusting blood-brain barrier(BBB)parameters.The NVU renews the concept of neuroprotection from a nerve protection to overall stabilization,promoting neuronal survival and neurological recovery,which reducing mortality.Previous studies showed that phenolic component D and H from Gastrodia elata Blume were effective for the CIRI.The main aim of the study was to investigate whether the D and H would play an important role during the process.The study also would explore the mechanism.Methods:The effects of the D and H were evaluated by using neurological scores,cerebral infarct volume,contents of EB and the ultrastructures of the NVU.The expression levels of the NVU’s symbolic proteins(Occludin,Claudin-5,MAP-2,GFAP and CD68)in damaged brain tissue were also detected by Western blot analyses.Results:1.The protective effect of the phenolic component D and H from Gastrodia elata Blume on the NVUWhen cerebral ischemia for 2h and reperfusion for 2 h was performed,the D and H had no obvious effect on the neurological score and infarct volume in the model rats.However,phenolic component D and H decreased EB’s content.When cerebral ischemia for 2h and reperfusion for 24 h was performed,compared with the model(MCAO/R)group,the neurological score,infarct volume,and EB’s content in groups treated by the D and H decreased significantly.In the D and H group,the ultrstructure of endothelial cells,basal lamina and tight junctions was preserved,the neuron injury was lessened,and the edema of glial cell and end-feet of astrocytes were also mitigated.2.Mechanisms involved in the phenolic component D and H from Gastrodia elata Blume on the NVUWhen cerebral ischemia for 2h and reperfusion for 2h was performed,the expression of Occludin,Claudin-5,MAP-2,GFAP and CD68 had no significant change in ischemic brain tissue of each group.When cerebral ischemia for 2h and reperfusion for 24 h was performed,the expression of Occludin and Claudin-5 in ischemic brain tissue in the D and H groups was increased,the expression of MAP-2 in ischemic brain tissue was not influenced,and the expression of GFAP in ischemic brain tissue were decreased.Besides,in the H group,the expression of CD68 in ischemic brain tissue was decreased.Conclusion:The phenolic component D and H from Gastrodia elata Blume showed protective effects on the NVU at cerebral ischemia for 2h and reperfusion for 24 h on MCAO/R rats.The mechanism the protective effects of the phenolic component D and H from Gastrodia elata Blume on the NVU was associated with enhancement of the expression of the BBB symbolic proteins,including Occludin and Claudin-5,and attenuation of the protein expression of the astrocyte symbolic protein GFAP.Besides,enhancement of the expression of the microglial symbolic protein CD68 could contribute the protective effects of the phenolic component H from Gastrodia elata Blume on the NVU.