LMWH Plays A Role Of Brain Protection By Promoting SUMO2/3 Protein Expression And Nuclear Transfer

Background:As a therapeutic drug of cerebral ischemia reperfusion injury,Low Molecular Weight Heparin is controversial.Because it is worried about that anticoagulation will affect the thrombus shift and bring bleeding risk.However,a series of studies have found that,in the early of CIRI,using low dose of LMWH can significantly reduce the cerebellar infarction volume and inflammatory factors’ producing in the edge area of infarction,without affecting the PT and APTT.Although the cerebral protective effect has been showed that Low Molecular Weight Heparin can inhibit the activation of Nuclear factor-kappa B(NF-kB)to reduce the inflammatory factors in recent years of study about the anti-inflammatory effect of Heparins,it remains no clear about the internal adjustment mechanism till now.Some studies reckon that LMWH may prevent the NF-kB nuclear transfer activation by physical combination way.Although to some extent,this theory can explain the phenomenon.But because there is no evidence to prove,it still can not be universally recognized.There are many similar studies in recent years,but few studies have involved the intermediate links in LMWH regulating the NF-kB activation.However,this research point has important theoretical value on LMWH in therapeutic areas,especially in the treatment of CIRI.In the recent years of studies,the researchers found that,in the early of CIRI,SUMO2/3 increased significantly in the edge area of the parietal cortex infarction.Then further studies found that this change can improve the nerve cells’ tolerance to CIRI and play a protective role to the half dark band of infarction.And this protective effect may be related to the ability that LMWH can suppress the activation of stress proteins such as NF-kB.In view of this,in the process of LMWH reduce the NF-kB activation,it need to be proved in research that whether SUMO2/3 plays a regulation effect in the middle.Our topic research is going to make a deep study in this question.The purpose is to know what effects to SUMO2/3 from LMWH in CIRI.Meanwhile,we also want to understand the function and meaning of SUMO2/3 in the process of LMWH reduce the NF-kB activation.Methods:In This Subject Research,we established the Middle cerebral artery occlusion(MCAO)model to simulate the brain ischemia reperfusion injury.We use LMWH as treatment.And western blotting,immunohistochemical(IHC)and immunofluorescence(IF)was used for experimental study.The research content including: 1.The effect of LMWH on brain tissue injury and nerve dysfunction of CIRI rats.2.The effect of LMWH on NF-kB activation and inflammatory factors’ producing in brain tissue of CIRI rats.3.The effect of LMWH on expression and nuclear transfer of SUMO2/3 protein in brain tissue of CIRI rats.Results:1.LMWH reduce the brain tissue injury of CIRI rats and improve the nerve dysfunction.1.1.Neurological function evaluation showed that MCAO resulted in severe neurological dysfunction in the rats,but LMWH intervention obviously attenuated the injury.1.2.Cerebral I/R injury induced severe cerebral infarction.However,LMWH alleviated the symptoms,and the effects were more significant in the striatum region that was sensitive to infarction.2.LMWH reduce the NF-kB activation and inflammatory factors’ producing in brain tissue of CIRI rats.Western blot results showed that the protein level of IL-1β and NF-κB P65 in I/R group was higher than that in sham operation group after 24 h reperfusion,while LMWH intervention obviously attenuated the level.3.LMWH reduce the expression and nuclear transfer of SUMO2/3 protein in brain tissue of CIRI rats.3.1.Western blot results showed that,after 3h reperfusion,SUMO2/3 protein expression level in I/R group was higher than that in sham operation group.But interestingly,after LMWH intervention,the expression level was significantly further increased(P<0.01).3.2.IHC and IF results showed that after 3h reperfusion,SUMO2/3 protein level in I/R group was higher than that in sham operation group,and nuclear transfer phenomenon appeared,mainly occurred in neurons.After LMWH intervention,the neurons that SUMO2/3 protein nuclear transfer occurred was significantly further increased.Conclusion:LMWH promoting the SUMO2/3 protein level and increasing nuclear transfer in CIRI,which possibly influence the NF-κB activation and inflammation extending.