The Effect Of BMSCs On The Release Of HMGB1 From Brain After Stroke

Background and Objective Stroke has become the second cause of death of the Chinese people, just less than the mortality of cancer. As China has gradually entered the aging society, stroke has become a major social problem. The occurrence of cerebral inflammatory after stroke has play an important role in the neuronal death and neurological deficits, so inhibiting inflammation could attenuate efficiently neurological deficits after stroke. Bone marrow stromal cells(BMSCs) is one of the most promising stem cell, which play an important role of protection by inhibiting the inflammatory reaction after stroke, but the specific mechanism has not yet been fully elucidated. HMGB1 is an important activator of inflammation at the early stage after the onset of stroke. Bone marrow stromal cells transplantation has been shown to has effects which can reduce the infarcted brain inflammation through immunoregulating effect, so we had the hypothesis that inhibition the release of HMGB1 is one of the mechanisms of inflammation inhibition,and designed the experiment to verify it. In this study, first,we made transient middle cerebral artery occlusion(Transient Middle Cerebral Artery Occlusion, t MCAO) mice model. Second, BMSCs were transplanted into animal intravenously.Methods First of all, BMMNCs were collected by gradient centrifugation using Ficoll lymphocyte separation medium. After culture and passage of BMMNCs, BMSCs were harvest, amplified, identified and preserved in low temperature conditon. Later, animal stroke models(t MCAO) were made according classical procedure of suture method. Then, animal models were randomly divided into three groups:sham, vehicle and BMSCs transplantation group, in which BMSCs were injected intravenously into mice. Stroke brain volume was calculated using TTC stain assay afterwards. After that, the degree of neurological deficit of each group were evaluated using m NSS scale. At the same time, we observed the release of HMGB1 in the nearby area of brain infarction by immunofluorescence technique and the expression of HMGB1, Bcl-2 and other inflammatory factors such as TNF-α and IL-1β using Western Blot technique. With all the experiments above, we could comprehensively evaluated the immunomodulatory effect of BMSCs after acute stroke in mice brain.Results Transplantation of BMSCs could efficiently reduce brain infarct volume and the expression of TNF-α and IL-1β after stroke, increase the expression of Bcl-2 and improve neurologic deficits. Compared with vehicle group, the release of HMGB1 was significantly less in transplantation group.Conclusion BMSCs transplantation could delay the progress of cerebral inflammatory response and significantly promote the neurological recover in mice after stroke. The therapeutic effect may be related to inhibition of the release and loss of HMGB1 from brain.