This study describes the use of the optical fiber luminescent oxygen sensors for the measurement of the oxygen partial pressure(P) spatiotemporal distribution in various cerebral regions of *** found that the distribu...
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This study describes the use of the optical fiber luminescent oxygen sensors for the measurement of the oxygen partial pressure(P) spatiotemporal distribution in various cerebral regions of *** found that the distribution of P in various cerebral regions was not only spatially heterogeneous,but also temporally heterogeneous - the trends of P dynamic changes were different in different cerebral *** P levels in parenchyma are stable,while in ventricles are fluctuating in a range of 3-6 torr within 3 *** optical fiber luminescent oxygen sensors presented here provided a reliable,sensitive and fast tool for real-time and continuous measurements of P levels in various brain regions of alive animals,and made the application of the luminescent methods for P detection extend to the whole brain of alive animals,which can also be used in the studies of hypoxic or ischemic brain injury and other states of metabolic dysfunction as well.
Neurogenesis in the adult brain occurs mainly within the two neurogenic structures, the dentate gyrus(DG) of the hippocampus and the sub-ventricular zone(SVZ) of the forebrain. It has been reported that mild hypoxia p...
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Neurogenesis in the adult brain occurs mainly within the two neurogenic structures, the dentate gyrus(DG) of the hippocampus and the sub-ventricular zone(SVZ) of the forebrain. It has been reported that mild hypoxia promoted the proliferation of NSCs in vitro. Our previous study demonstrated that external hypoxic environment stimulates neurogenesis in the adult rat brain in vivo. However, it is unknown that how hypoxic environment affects the oxygen content in brain and result in neurogenesis. Here we use an opticalfiberluminescentoxygen sensor to detect the oxygen content in adult rat brain in situ under normoxia and hypoxia. We found that the distribution of oxygen in cerebral regions is spatiotemporally heterogeneous. The Po2 value in the ventricles and DG of the brains are much higher than that in the other parts of the brain(Po2 level is about 10 torr in the DG, and 45～50 torr in the ventricles);While, in the other parts, like cortex and thalamus, the Po2 always remains about 2 torr. Interestingly, our in vivo studies evidenced that external hypoxia environment could change the intrinsic oxygen content in brain tissue, especially, reduced the oxygen levels in both DG and sub-ventricular zone which are the major parts where adult neurogenesis take place. Furthermore, hypoxic environment also increases the expressions of HIF-1/VEGF in DG and SVZ, which have been reported in regulation of neurogenesis. We first evidenced that along with the external environment of the oxygen content decreased, the PO2 levels in DG and SVZ were decreased. The reduced oxygen content in DG and SVZ could be the main causes to trigger neurogenesis in the adult brain. More importantly, we speculate this putative oxygen may be the physiological bases that maintain neurogenesis in restricted area in adult brain.
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