ABSTRACT
OBJECTIVE@#To explore the expression profile of Ephrin-B2 in the ischemic penumbra after transient focal cerebral ischemia in rats, and to clarify the mechanism of Ephrin-B2 triggering angiogenesis.@*METHODS@#Sprague-Dawley rats were randomly divided into a normal group, a sham operation group and ischemic-reperfusion 1, 3, 7, 14, and 28 d groups. Suture-occluded method was used to establish the focal middle cerebral artery occlusion model and the ischemic brain was reperfused 2 h after the occlusion. Western blot and quantitative real-time reverse-transcription polymerase chain reaction were used to detect the dynamic expression profile of Ephrin-B2 in the penumbra cortex. Double immunofluorescence was used to speculate the location and the co-expression of Ephrin-B2 in blood vessels, neurons and astrocytes. Microvessel density was quantified by the number of CD31+ cells. Rats were subjected to neurologic functional tests by modified neurological severity scores (mNSS) before sacrifice.@*RESULTS@#Compared with the sham group, Ephrin-B2 protein and mRNA level of the penumbra cortex in the ischemic group increased 3 days (P<0.05) after the reperfusion, peaked at day 7 and 14 (P<0.01), and declined at day 28. Double immunofluorescence indicated that Ehprin-b2 was expressed in the neurons, blood vessels and astrocytes; mNSS peaked at day 7, and gradually declined at day 14. The microvessel density of penumbra cortex in the ischemic group increased 3 days (P<0.05) after the reperfusion, peaked at day 14 (P<0.01), and gradually declined at 48 h.@*CONCLUSION@#Cerebral ischemia reperfusion induces the over-expression of Ephrin-B2, with a dynamic trend, suggesting that Ehprin-b2 may improve post-stroke functional recovery by enhancing angiogenesis and neurogenesis.
Subject(s)
Animals , Rats , Astrocytes , Metabolism , Brain , Pathology , Brain Ischemia , Metabolism , Cerebral Cortex , Metabolism , Ephrin-B2 , Metabolism , Infarction, Middle Cerebral Artery , Ischemic Attack, Transient , Neurons , Metabolism , Rats, Sprague-Dawley , Reperfusion Injury , MetabolismABSTRACT
BACKGROUND: Basic fibroblast growth factor (bFGF) can accelerate the bone marrow mesenchymai stem cells (BMSCs) proliferation and differentiation into nerve cells, which is considered as a mitogen of glial cells.OBJECTIVE: To investigate the survival and differentiation of bFGF gene modified BMSCs transplanted on rat models of cerebral ischemia by double immunofluorescence staining, and to study the differentiation trend of BMSCs into neuron-like cells and glial cells.DESIGN, TIME AND SETTING: The randomized control animal experiment was completed in the central laboratory of Experimental Animal Center of Central South University from July 2005 to March 2006.MATERIAL: Fifty Sprague-Dawley rats were divided into 4 groups at random: sham operation group (n=10), cerebral ischemia-reperfusion injury group (n=10), BMSCs group (n=i5) and bFGF modified BMSCs group (n=15). METHODS: Except sham operation group, rats in the other three groups were prepared for local cerebral ischemia-reperfusion models. Then BMSCs or bFGF modified BMSCs were intravenously transplanted into cerebral ischemic rats, and the same volume of DMEM were injected in the cerebral ischemia-reperfusion injury group. MAIN OUTCOME MEASURES: Survival rate and differentiation of grafted cells were observed by 5-bromo-2-deoxyuridine (BrdU)-NeuN, and BrdU-glial fibrillary acidic protein (GFAP) double immunofluorescence staining; the neurological scores and infarction volumes in each group. RESULTS: At 7 days after implantation, the number of BrdU/NeuN-positive cells and BrdU-GFAP-positive cells in the bFGF modified BMSCs group was higher than those on the BMSCs group (P < 0.05), but there were no significant differences in the co-expression cells by double immunofluorescence staining between the two groups (P > 0.05). At 7 days following reperfusion, neural function of cerebral ischemia rats were improved and infarction volume was reduced in both BMSCs group and the bFGF modified BMSCs group, and bFGF modified BMSCs group was superior to BMSCs group. CONCLUSION: BMSCs modified by bFGF can survive in cerebral ischemic region and differentiate into neuron and glial cells, which are more proper for repairing nerves.