Effect Of Hyperbaric Oxygen On Angiogenesis In The Brain Of Adult Rats With Cerebral Ischemia-reperfusion Injury

Cerebrovascular disease is a common disease, and of which, ischemiccerebrovascular disease account for the largest proportion. Althoughthrombolysis and antithrombotic therapy and rehabilitation treatment played aimportant role in reducing mortality and morbidity of acute cerebral infarctionand promoting neurological function, overall, ischemia stroke is still a lack ofeffective treatment. Hyperbaric oxygen (HBO) has been recognized as anon-invasive therapy on cerebrovascular disease. Recent studies of home andabroad show that HBO therapy can reduce edema, protect blood brain barrier,decrease infarction volume and promote neurologic function, and so on. But thespecific mechanisms are still unclear and that HBO therapy can promote cerebralangiogenesis or not has not been reported.In this study, we adopted adult rat middle cerebral artery occlusion(MCAO), compared with NBO treatment, and observed the effect of HBOtherapy on cerebral angiogenesis in adult rats after ischemia-reperfusion injury, inorder to provide new ideas and new theory evidences for further elucidating mechanisms of HBO treatment on cerebral ischemia-reperfusion injury. In thisstudy, adult Sprague-Dawley (SD) male rats were randomly divided into shamsurgery group (SS group), ischemia-reperfusion group (IR group), normobaricoxygen group (NBO group) and hyperbaric oxygen group (HBO group). Weadopted suture method to make MCAO model. After cerebral ischemia for1.5hours, the middle cerebral arterys were treated with reperfusion. We observed theeffect of HBO therapy on cerebral angiogenesis by tissue sections and TTCstaining and immunohistochemical staining and western blotting.The results of the study showed as following:1. Neurologic symptom score: the rats in each groups had no difference after2hour of operation that it was almost awake and had moderat neurologicaldysfunction symptom.Compared with NBO and IR group, the rats in HBO groupimproved neurological dysfunction symptom in7and10days, and the differenceof neurologic symptom score had statistically significant.2. The results of stain in TTC: the all brain slices were red in SS group whileit had white infarction in IR group which mainly distributed in cortical andsubcortical tissue, or even involving the intire right hemisphere. Compared withIR group in the same time dot, the infarction volme decreased notablely in theHBO group rats, especially in7and10days group, and the differences hadstatistically significant.3. The results stained by immunohistochemistry(1) The results of CD34and VEGF and Flt-1stained by immunohisto-chemistry: The positive cells of CD34distributed in microvessel were mostlybrown yellow cords, only small numbers were round and oval. The positive cellsof VEGF and Flt-1expressed in vascular endothelial cells were brown round andoval. positive cells of CD34and VEGF and Flt-1only had a small amount of expression and scattered distribution in SS group. Compared with SS group, theexpression of positive cells of CD34and VEGF and Flt-1increased in IR andNBO and HBO groups. The positive cells expressed mainly in the cortexinfracted surrouding areas and very few in the infarct zone and conralateralnon-infarcted areas. Compared with IR group in each time, NBO group and IRgroup have no difference in positive cells expression of CD34and VEGF andFlt-1. Compared with IR and NBO group, positive cells significantly increased inevery time dot in HBO group, especially in7and10days.(2) The results of GFAP stained by immunohistochemistry: The positivecells are brown and like star, and consists of bodies and synapses. positive cellsonly had a small amount of expression and stained light in SS group. Comparedwith SS group, the positive cells in IR group increased. Compared with IRgroup, the positive cells significant increased and cell body hypertrophy, deepstaining in HBO group.4. The result of Western blot show that, compared with SS group, theexpression of CD34increased obviously in IR and HBO group. Compared withIR group, the expression of CD34increased notablely in HBO group at7and10days, which is consistent with the results of immunohistochemistry.In a word, through this study we can learn that, HBO treatment caneffectively increase the number of new microvascular, restore local circulation,decrease infarction volume, promote the expression of GFAP, improveneurologic function. HBO treatment is more effective than NBO treatment inpromoting angiogenesis after adult rats cerebral ischemia-reperfusion injury.