Catalase was measured according the method previously described[27]. The assay
mixture consisted of 975μlH2O2 (25 mM) and 25 μl of the tissue homogenates.
Changes in absorbance were recorded at 240 nm for 2 min. Catalase activity was
expressed as nanomoles H2O2per minute per microgram protein.
Isoprostane was examined with an ELISA commercial kit (Cayman Chemical
Corporation, Ann Arbor, MI, USA) following the manufacturer's protocol.