Study On Protect Of Hyperbaric Oxygen Therapy On Cerebral Ischemia-reperfusion In Adult Rats And Its Mechanism

Cerebrovascular disease has been considered to be a kind of vital disease at present, and of which, ischemic cerebrovascular disease is the most common kind. Recent studies show that hyperbaric oxygen (HBO) on the treatment of ischemic cerebrovascular disease with good results, can significantly reduce brain edema, decrease infarction volume and improve neurological function, but the specific mechanisms still unclear. With the introduction of the concept of neural stem cells (neural stem cells, NSCs) and the progress of the study, more and more scholars began to link HBO with NSCs, want to explain the mechanisms of treating ischemic brain injury by the impact of HBO on NSCs. However, because of inconsistencies in animal model selection, HBO treatment schedule differences and some other reasons, there is no clear conclusions at present.In this study, adult rat middle cerebral artery occlusion (MCAO) model was adopted. We observed the effect of HBO therapy on NSCs proliferation and vascular endothelial growth factor (VEGF) in adult rat brain after ischemia-reperfusion injury, in order to provide new experimental evidence and new ideas for further elucidating mechanisms of HBO therapy. In this study, adult male SD rats were randomly divided into sham surgery group (SS), ischemia-reperfusion group (IR) and hyperbaric oxygen treatment group (HBO). MCAO model was performed by suture method. After being blocked for 1.5 hours, the arterys were treated with reperfusion. By TTC staining, the changes of the infarction volume were observed at different time points after ischemia-reperfusion. By immunohistochemical staining the effect of HBO treatment on NSCs proliferation at different time points and long-term HBO treatment on angiogenesis in ischemic area were observed. Results were showed as following:(1) TTC staining revealed that SS group infarction was not found and HBO group infarction rate decreased compared with IR group at different time points after ischemia-reperfusion, of which 11 and 31 days at the point decreased obviously(P<0.05).(2) Compared with SS group, the numbers of BrdU and Nestin positive cells in the cortex and the striatum were significantly increased in each IR group at different time points after ischemia-reperfusion(P<0.05), and the positive expression increased. In HBO group, the numbers of BrdU and Nestin positive cells were all markedly increased compared with IR group at 11 and 31 days after ischemia-reperfusion(P<0.05).(3) After 30 d HBO treatment, VEGF expression was decreased obviously compared with IR group(P<0.05), and both were higher than SS group(P<0.05). CD34 in SS group did not express, in HBO group expressed less than IR group, but no significant difference(P>0.05).In conclusion, through this study we found that, HBO therapy can effectively promote rat neural stem cells proliferation after ischemia-reperfusion injury, which eventually leads to the occurrence of migration and differentiation, and the long term HBO therapy can protect the nerve cells by the regulation of VEGF expression, then contributes to the brain self-reparation and nerve function recovery.