Effects Of Bone Mesenchymal Stem Cells Transplantation Combined With Therapeutic Mild Hypothermia On Recovery Of Neurological Functions And Its Mechanisms In Cerebral Ischemia Injury In Rats

Background and PurposeIschemia stroke is one of the main central nervous system(CNS)disease,which causes greatly high mortality rate and disability rate.Nevertheless,up till now,no proper and effective treatments have been figured out to promote the regeneration of nerve cells.Numerous studies have illustrated that BMSCs(Bone Marrow Mesenchymal Stem Cells)transplantation could reduce infarction size and promote recovery of neurological function on rats with acute ischemia stroke.Mild hypothermia,where the brain temperature stays at 32-35?,also has been proved to bear the functions of lessening infarction size,promote angiogenesis,reduce cerebral edema and ameliorate neurological outcomes.Therefore,this study aims to fully examine the impacts and protective mechanisms of BMSCs transplantation combined with therapeutic mild hypothermia after cerebral ischemia injury on rats,and provide the theoretical basis for clinical application.MethodsBMSCs were isolated using density gradient centrifugation method combined with adherent screening method,followed by purification,culture,identification and labeling with DAPI.The middle cerebral artery occlusion(MCAO)model was established by suture methocd,followed by the implementation of mild hypothermia treatment for 3 hours.24 hours after MCAO,ateral ventricle transplantation was operated.All rats were examined at five respective time-points:before MCAO,before transplantation,at 1 day,5 day and 10 day time-point after transplantation operation for tests on neurological function by means of mNSS(modified Neurological Severity Score).The percentage of infarction size was calculated by TTC staining.Using immunofluorescence staining to detect the expression and variation tendency of protein GFAP(Glial Fibrillary Acidic Protein)and VEGF(Vascular Endothelial Growth Factor)under 400X microscope.ResultsAfter MCAO operation,the neurological deficits were obvious with the left limb paralysis in varying degrees.BMSCs transplantation combined with mild hypothermia treatment significantly decreased mNSS score(P<0.01)and reduced infarction size(P<0.01)better than single treatment.Immunofluorescence staining showed that the number of DAPI+GFAP+ and DAPI+VEGF+ double-labeled positive cells and the expression of GFAP and VEGF increased sharply in the combination therapy group,better than single treatment.ConclusionsTwo types of therapeutic mechanisms of cerebral protection have different emphases,but complementary,and the combination therapy can give full play to the advantages of two treatment programs to lessen the infarction size and improve neurological function further.