The Effect Of Neovascularization On Human Retinal Pigment Epithelium After Hyperbaric Oxygen Therapy

IntroductionHyperbaric oxygen therapy (HBO) is used in a number of medical conditions, the HBO’s ability to raise oxygen tension maybe helpful toward ocular hypoxic diseases, such as diabetic retinopathy. Under hypoxic conditions the retinal pigment epithelial cells release angiogenic factors such as VEGF, HIF-1 and TNF-α and decrease the level of antiangiogenic factors such as PEDF. The decrease of angiogenic factors and the increase of antiangiogenic factors can suppress the formation of neovascularization, a complication of ocular hypoxic diseases.ObjectiveTo investigate the neovascularization effect of hyperbaric oxygen therapy on human retinal pigment epithelium cells (ARPE-19).MethodHuman REP cells were cultured in vitro, and divided into normoxic control group (non-hypoxic group, which was under DMEM/F12 broth) and hypoxic control group (which was under DMEM/F12 and CoC12 broth) randomly. The experimental groups were then divided into three subgroups via the different HBO pressure, 0.15 MPa exposed group,0.2MPa exposed group, and 0.25MPa 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 PEDF and TNF-α by RPE cells were measured by western blot.ResultWestern Blot test showed the levels of PEDF expression by RPE cells in both normoxic and hypoxic experimental groups had an increased trend as the pressure increases with statistical significance (P<0.01). The results showed that the expression of PEDF in the normoxic group was higher when compare to the hypoxic group. The expression of PEDF level showed no statistical significance to the duration of the HBO exposure. The results showed that the level of TNF-α expression by RPE cells in both normoxic and hypoxic 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 expression of TNF-α level showed no statistical significance to the duration of the HBO exposure.Conclusion1) HBO increases the release of PEDF by RPE cells in both normoxic and hypoxic conditions.2) HBO decreases the release of TNF-α by RPE cells in both normoxic and hypoxic conditions, especially in hypoxic conditions.3) HBO can raise the level of PEDF and decrease the level of TNF-α in RPE cells, and has an antiangiogenic effect that can suppress the formation of neovascularization.