Objective: To study the effect of hyperbaric oxygen (HBO) administered at different pressures and different exposure time on the differentiation of neural stem cells (NSCs) in vitro.
Methods: The cerebral cortices from newborn rats (0-3 days old) were sterilely collected, digested, and centrifuged. After removal of the supernatant, the cells were re-suspended with DMEM/F12 medium containing B27, bFGF and EGF. The NSCs of 2-3 passages were randomly divided into seven groups: a control (untreated) and 6 HBO treatment groups that NSCs were subjected to HBO treatment of different pressures (1, 2 or 3 ATA) and different exposure time (30 or 60 minutes). The differentiated NSCs were examined by neuron-specific enolase (NSE) immunocytochemistry 24 hrs later. Percentage of NSE positive cells differentiated from NSCs was assessed by fluorescent microscopy.
Results: The percentage of NSE positive cells differentiated from NSCs was the highest in the HBO 2ATA-60 min group (9.17+/-0.50%) (P<0.01), followed by the HBO 3ATA-60 min (7.89+/-0.62%), HBO 2ATA-30 min (6.72+/-0.76%), HBO 3ATA-30 min (6.08+/-0.57%), HBO 1ATA-60 min (5.45+/-0.52%), HBO 1ATA 30 min (3.85+/-0.44%) and control groups (3.72+/-0.88%). In addition to the HBO 1ATA-30 min group, the other HBO treatment groups had increased significantly percentage of NSE positive cells compared with the control group (P<0.01). Under the same pressure, the 60 min treatment groups had increased significantly percentage of NSE positive cells compared with the 30 min treatment groups (P<0.01).
Conclusions: HBO treatment (2 ATA, 60 minutes) produces a best effect in the differentiation of NSCs into neurons.