ABSTRACT
Objective To investigate the effect of hyperbaric oxygen intervention at different time on the neural stem cell proliferation and differentiation in dentate gyrus subgranular zone (SGZ) of adult rats after acute focal cerebral ischemia.Methods Totally 48 Sprague-Dawley male adult rats were randomly divided into a middle cerebral artery occlusion (MCAO) group, a hyperbaric oxygen group, a hyperbaric air group and a normobaric oxygen group, each of 12.A middle cerebral artery occlusion (MCAO) model was induced to all rats using the modified Zea-Longa's method of intraluminal filament occlusion, Except the MCAO group, the other 3 groups received corresponding hyperbaric oxygen, hyperbaric air and normobaric oxygen intervention once a day two hours after the suture insertion.The rats were sacrificed for double-label immunofluorescent analysis at 2 days, 3 days, 7 days and 14 days after brain ischemia.BrdU +/nestin + labeled the proliferated neural stem cells, and BrdU +/DCX + labeled its differentiated derivates, early neurons, in SGZ of ischemic hippocampus dentate gyrus.Also, the cell number was calculated under the fluorescence microscope.Results Two days after brain ischemia, the numbers of BrdU/nestin and BrdU/DCX cells in SGZ in the hyperbaric oxygen group were (2340.45 ± 1109.59) and (5520.66 ± 1103.09) respectively, which had increased significantly, compared with the hyperbaric air group and normobaric oxygen group (P ＜ 0.05).Three and 7 days after brain ischemia, the numbers of BrdU/nestin and BrdU/DCX cells in SGZ in the hyperbaric oxygen group had shown significant increase compared with the other 3 groups (P ＜ 0.05).Fourteen days after brain ischemia, the numbers of BrdU/DCX cells in SGZ in the hyperbaric oxygen group had significantly increased compared with the hyperbaric air group, normobaric oxygen group and the MCAO group (P ＜ 0.05).Conclusion Hyperbaric oxygen promotes the proliferation and differentiation of neural stem cells in ischemic SGZ.