| Cerebral ischemic stroke(CIS),also known as cerebral infarction(CI),is a severe acute disease caused by cerebral vascular embolism or occlusion,resulting in blood and oxygen supply disorder in the corresponding blood supply area,which will eventually lead to the appearance of neurological dysfunction or tissue damage.Severe cases may even cause death.Globally,CIS plays an important role in causes of death or disability in adults.At present,although intravenous and arterial thrombolysis have been widely employed in clinical treatment of CIS,there are still some limitations in clinical applications.A new neuroprotective or recovery agent is urgently needed to reduce the injury,delay the pathological process,or promote the recovery of neurological function after CIS.Natural borneol(NB)is a lipid-soluble monoterpenoid that has a transdermal effect which can increase the permeability of blood-brain barrier(BBB).In the treatment of CIS,NB can protect the nervous system by improving energy metabolism in ischemic brain tissue,inhibiting oxidative stress,and reducing inflammatory responses.However,the time effect NB on the BBB permeability and its protective mechanism against CIS have not been fully clarified.In this study,experiments were conducted to explore the time effect of NB on BBB permeability,find out the peak time of its open BBB,and explore its protective mechanism for CIS,which may provide new choice of agent for clinical treatment.Experiment Purpose1.To ascertain the time effect of NB on the BBB permeability in Kunming mice(KM mice).2.Edaravone(ED),a commonly used agent for clinical treatment of cerebral ischemic stroke,was employed as a reference to evaluate the effect and mechanism of NB on the treatment of cerebral ischemic stroke.Research Methods1.To explore the time effect of intraperitoneal injection of NB on the permeability of the BBB.Evan’s blue(EB)was employed as a tracer to detect the content of EB that entered the brain tissue after intraperitoneal injection of NB for 0 min,10 min,30 min,60 min,120 min,480 min,respectively.2.The photochemical method was employed to prepare the ischemic model of the left middle cerebral artery in KM mice.The mice were divided into the NB treatment group and the ED treatment group randomly.Besides that,the sham operation group and the model group were set.24 h after the model was successfully established,we applied Zea Longa score method,cylindrical test,balance beam test,and foot failure test to evaluate the neurological function of the test mice.TTC staining were performed to observe and compare the infarct volume in KM mice.The water content of mouse brain was determined by dry-wet weighing method to assess the edema of brain tissue in the ischemic model.With the immunofluorescence staining by Neuro-N,apoptosis of neurons was observed intuitively.In addition,changes of caspase-3 and MMP-9 in the ischemic brain tissue were detected by immunofluorescence staining.ResultsThe content of EB in the brain,cerebellum,and brainstem was measured after intraperitoneal injection of NB for 0 min,10 min,30 min,60 min,120 min and 480 min,respectively.The results showed that in the six time points selected in this study,the content of EB was highest in the brain and cerebellum after intraperitoneal injection of NB for 30 min,while the EB content reached the peak after injection of NB for 60 min in brain stem.2.After 24 h of photochemical cerebral ischemia model establishment,compared with the model group,the neurological deficits in the group with NB treatment were significantly improved.The results of TTC staining showed that the volume of CIS in the n NB group was significantly lower than that in the model group 24 h after the model was built.After 24 h of model construction,the water content of brain tissue in the NB treatment group was significantly reduced compared with that in the model group.The protective mechanism of NB in cerebral infarction was detected by immunofluorescence.The staining results showed that in the model group,Neuro-N expression was low,while caspase-3 and MMP-9 were highly expressed.However,in the NB-treated group,Neuro-N expression was higher than the model group and the expression levels of caspase-3 and MMP-9 were significantly decreased.Conclusion1.NB can regulate the permeability of BBB.2.NB can improve neurological deficits,reduce brain edema,decrease infarct volume in brain,increase blood perfusion in ischemic penumbra after cerebral ischemic stroke.3.Treatment with NB can attenuate neuronal apoptosis. |
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