ABSTRACT
Objective To investigate the protective effect and mechanism of propofol on the blood-brain barrier in rats with cerebral ischemia.Methods A total of 48 10-week-old male SD rats were randomly divided into the sham group,the cerebral ischemia group,the propofol group and the propofol+LY294002 group.Twenty-four hours before the induction of the model,the rats in the propofol+LY294002 group were intracerebroventricularly injected with PI3K inhibitor LY294002(0.3 mg·kg-1),and the rats in the other groups were administrated with saline(10 μL).Rats in the cerebral ischemia group,the propofol group and the propofol+LY294002 group established cerebral ischemia models by carotid artery occlusion.Rats in the sham group only isolated the common carotid artery and ligated the external carotid artery without other treatment.During the modeling period,the rats in the propofol group and the propofol+LY294002 group were given propofol(10 mg·kg-1)via the tail vein,and the sham group and the propofol group were treated with saline.After 24 hours,the neurological function of rats was evaluated by Zea Longa method;the area of cerebral infarction was detected by TTC staining;the degree of cerebral edema was detected by the dry-wet weight method.EB tracer method was used to evaluate the integrity of the blood-brain barrier;ELISA was used to detect inflammatory cytokines in cerebrospinal fluid;Western blot was used to detect the expression of PI3K/AKT signaling pathway proteins and blood-brain barrier tight junction proteins Claudin-5 and Occludin.Results Cerebral ischemia led to the increase of neurological function scores and local infarction of brain tissues in rats.Compared with the sham group,the EB content in the brain tissue of rats in the cerebral ischemia group increased,the degree of brain edema increased,and the content of inflammatory cytokines in the cerebrospinal fluid increased.And the use of propofol could significantly decrease the neurological function scores,reduce the area of cerebral infarction,inhibit EB penetrating blood-brain barrier,reduce the degree of brain edema,reduce the release of inflammatory cytokines,and up-regulate the expression of PI3K/AKT signaling pathway proteins and tight junction proteins Claudin-5 and Occludin.LY294002 significantly reversed the above effects of propofol.Conclusion Propofol can maintain the expression of tight junction proteins Claudin-5 and Occludin through the PI3K/AKT signaling pathway,protect the structural and functional integrity of blood-brain barrier,reduce the degree of brain edema,prevent other inflammatory cytokines into the brain tissue,reduce cerebral infarction,and alleviate the neurological functional damage caused by cerebral ischemia.