An in vitro hyperbaric oxygen system for evaluation of free radical damage and protection by catechins on hemorheological parameters.

Free radicals play a critical role in causing hemorheologic abnormality which is highly correlated with cardiovascular disease and stroke. In this study, we established an in vitro model to evaluate the influence of free radical attacks on hemorheological parameters. A well-sealed chamber with hyperbaric oxygen was used to simulate an environment of free radical attacks. Hemorheological parameters, including whole blood viscosity, erythrocyte membrane lipid peroxidation, and erythrocyte deformability, were investigated. We then used the in vitro model to evaluate the anti-free radical effects of some well-known catechin antioxidants, such as epigallocatechin gallate (EGCG), (-)-epicatechin 3-gallate (ECG), and (-)-epigallocatechin (EGC) on abnormal hemorheological parameters induced by hyperbaric oxygen. The results show that an increase in oxygen partial pressure (1.0, 1.5, 2.0 and 2.5 atm) and exposure time (4, 8, 12 and 16 h) resulted in elevated free radical formation and viscosity of whole blood, enhanced lipid peroxidation in erythrocyte membranes, but decreased erythrocyte deformability. In addition, EGCG, ECG, and EGC (0.1, 0.5 and 1.0 μM) effectively ameliorated hemorheologic abnormality and enhanced erythrocyte deformability. Therefore, this study has provided an in vitro hyperbaric oxygen model to rapidly screen or assess the efficacy of functional foods and drugs in the prevention or improvement of hemorheologic abnormality.