Inducible nitric oxide synthase and cyclooxgenase-2 mediate protection of hydrogen peroxide preconditioning against apoptosis induced by oxidative stress in PC12 cells.

The induction of inducible nitric oxide synthase (iNOS) in response to different stress is associated with simultaneous induction of cyclooxygenase-2 (COX-2) in various cell types. Both iNOS and COX-2 have been reported to mediate the late phase of cardioprotection induced by different preconditioning. However, whether both iNOS and COX-2 are mediators in the neuroprotection induced by preconditioning with hydrogen peroxide (H(2)O(2)) at low concentration is unknown.

Hydrogen peroxide preconditioning protects PC12 cells against apoptosis induced by oxidative stress.

Oxidative stress can induce significant cell death by apoptosis. We explore whether prior exposure to H2O2 (H2O2 preconditioning) protects PC12 cells against the apoptotic consequences of subsequent oxidative damages and what role the ATP-sensitive potassium (K(ATP)) channels play in the preconditioning protection. PC12 cells were preconditioned with 90 min exposure to H2O2 at 10 micromol/L, followed by 24-h recovery and subsequent exposures to different concentrations (20, 30, 50 and 100 micromol/L) of H2O2 for 24 h respectively.