sentence: A global gene expression analysis of aged oocytes in mice revealed the decrease in mRNA expression of mitochondrial antioxidant genes , peroxiredoxin 3 ( Prdx3 ) and thioredoxin 2 ( Txn2 ) , as well as cytosolic antioxidant genes , glutaredoxin 1 ( Glrx1 ) , glutathione S-transferase mu 2 ( Gstm2 ) , and superoxide dismutase 1 ( Sod1 ) ( 49 , 50 ) .