Taurine protection of PC12 cells against endoplasmic reticulum stress induced by oxidative stress.

BACKGROUND: Taurine is a free amino acid present in high concentrations in a variety of organs of mammalians. As an antioxidant, taurine has been found to protect cells against oxidative stress, but the underlying mechanism is still unclear. METHODS: In this report, we present evidence to support the conclusion that taurine exerts a protective function against endoplasmic reticulum (ER) stress induced by H2O2 in PC 12 cells. Oxidative stress was introduced by exposure of PC 12 cells to 250 uM H2O2 for 4 hours. RESULTS: It was found that the cell viability of PC 12 cells decreased with an increase of H2O2 concentration ranging from approximately 76% cell viability at 100 uM H2O2 down to 18% at 500 uM H2O2. At 250 uM H2O2, cell viability was restored to 80% by taurine at 25 mM. Furthermore, H2O2 treatment also caused a marked reduction in the expression of Bcl-2 while no significant change of Bax was observed. Treatment with taurine restored the reduced expression of Bcl-2 close to the control level without any obvious effect on Bax. Furthermore, taurine was also found to suppress up-regulation of GRP78, GADD153/CHOP and Bim induced by H2O2, suggesting that taurine may also exert a protective function against oxidative stress by reducing the ER stress. CONCLUSION: In summary, taurine was shown to protect PC12 cells against oxidative stress induced by H2O2. ER stress was induced by oxidative stress and can be suppressed by taurine.