Intravenous administration of Tempol did not affect excretion of TBARS in CON and CKD groups compared to vehicle, whereas PEG-catalase decreased TBARS excretion in CKD group (P<0.05) and showed a trend to decrease in CON group compared to vehicle (P = 0.09) (Fig. 8). The gene discussed is CAT; the disease is chronic kidney disease.