I-Chen Sandra Chao, Luan Jie and Jian-Kang Chao
Objective: To investigate the neovascularization effect of hyperbaric oxygen (HBO) therapy on human retinal pigment epithelium (REP) cells. Methods: Human REP cells were cultured in vitro, and divided into normoxic control group and hypoxic control group randomly. The experimental groups were then divided into three subgroups via the different HBO pressure, 0.15 MPa exposed group, 0.2 MPa exposed group, and 0.25 MPa exposed group. The experimental groups were exposed to 100% pure oxygen for 60 and 90 minutes twice, with a 24 hours interval. After HBO exposure the expression of pigment epithelium-derived factor (PEDF) and tumor necrosis factor alpha (TNF- α) by RPE cells were measured by western blot. Results: The western blot result showed that the level of PEDF expression in both experimental groups had an increased trend as the pressure increases with statistical significance (P<0.01). The expression of PEDF in the normoxic group was higher than the hypoxic group. The results showed that the level of TNF-α expression by RPE cells in both experimental groups have a decrease trend as the pressure increases with statistical significance (P<0.01). The results showed that the expression of TNF-α in the hypoxic group was higher when compared to the normoxic group. The duration of HBO exposure has no statistical significance on the level of PEDF and TNF- α expression. Conclusion: This study supports the idea that HBO increases the release of PEDF by RPE cells whither in normoxic and hypoxic conditions, and decreases the release of TNF- α by RPE cells in both conditions, especially in hypoxic state. We also found that HBO can raise the level of PEDF and decrease the level of TNF- α in RPE cells, and has an anti-angiogenic effect which can suppress the formation of neovascularization.
