Cytomembrane ATP-sensitive K~+ Channels In Neurovascular Unit Targets Of Ischemic Stroke In The Recovery Period

ObjectiveTo study the values of nerve vascular unit in ischemic stroke recovery period and three cell signal transduction pathways including mitogen activated protein kinase P38-MAPK pathway, the cell membrane of ATP sensitive potassium channel and cell apoptosis and inflammatory response mediated by poly two phosphate transferase-1 on Neural function recovery,to demonstrated Possiblly potential therapeutic targets.MethodsTo construct middle cerebral artery occlusion (MCAO) model in rats by thread embolism method,this study was composed by three experiments.The first experiment was done as follow:The mice were divided randomly into three groups,sham operation group, MCAO group and P38 antagonists group,and each of 6 samples. The sham operation group was only exposed the related anatomies,not by thread embolism,then sutured directly the whole layers.The antagonists group was injected SB203580(5mg/kg, dissolved into 5mg/ml DMSO) into abdomen 30 min before constructing the model.Then to compare cerebral infarction areas by TTC staining method, p38a and p38β positive rate by immunohistochemical staining, P38 total protein expression level by Western Blot after 3 days. The second experiment was done as follow:The mice were divided randomly into four groups, sham operation group, MCAO group,KATP blocking agent group,and KATP open agent group, each of 6 samples.The blocking agent group was injected 5-hydroxydecanoate (5-HD, 40mg/Kg), into abdomen and open agent group was injected diazoxide (40mg/Kg) into abdomen 3 days after constructing the model,the sham operation group and MCAO group were injected equivalent normal saline.Then to compare cerebral infarction areas by TTC staining method, kir6.1、SUR1和SUR2 mRNA expression levels by RT-PCR. The third experiment was done as follow:The mice were divided randomly into three groups, sham operation group, MCAO group, and PARP-1 inhibitor group, each of 6 samples.The PARP-1 inhibitor group was injected PARP-1 inhibitor(AG 14361,5mg/kg, dissolved into 5mg/ml DMSO) into abdomen 30 min before constructing the model;to sacrificed and get the materials 3 days after normal feeding.Then to compare neural function score by balance beam experiment, tissue apoptosis rate by TUNEL method, P53、Fas、NF-κB protein expression levels by Western Blot.ResultsThe first experiment:The cerebral infarction areas in P38 antagonists group was significantly smaller than MCAO group (P<0.05).The p38a和p38β positive rates in MCAO group were significantly higher than P38 antagonists group (P<0.05). p38 total protein expression level in MCAO group was also significantly more than P38 antagonists group (P<0.05).The second experiment:The cerebral infarction areas in KATP open agent group was significantly smaller than MCAO group and blocking agent group,the cerebral infarction area of blocking agent group was the most (P<0.05).The kir6.1、SUR1和SUR2 mRNA expression levels in open agent group were highest,then the MCAO group and blocking agent group, sham operation group was lowest (P<0.05).The third experiment:The neural function score in PARP-1 inhibitor group was significantly higher than MCAO group (P<0.05).The Tissue apoptosis rate in inhibitor group was significantly lower (P<0.05).The P53、Fas、NF-κB protein expression levels in inhibitor group were all significantly lower (P<0.05).ConclusionThe three cell signal transduction pathways,that is P38-MAPK pathway, KATP channel and PARP-1 could all play important roles on neural function injury and recovery of nerve vascular unit in Ischemic stroke recovery period,interventing them may be effectively potential therapeutic targets.