THE RELATIONSHIP OF IRON AND GLYCOGEN TO THE IN-VITRO, ULTRAWEAK CHEMILUMINESCENT ANALYSIS OF LIPID-PEROXIDATION IN RABBIT HEARTS OF VARYING AGES

Oxidative stress, which occurs when prooxidants overwhelm antioxidants , has been implicated as a cause of tissue damage related to ischemia and reperfusion. Neonatal animal and human hearts have been shown to d iffer in their response to oxidative stress, but the mechanism for thi s difference is unclear. To study this phenomena, crude homogenates of hearts from 4-day, 4-week, and adult (>6 months) New Zealand rabbits were studied by chemiluminescence after exposure to O-2/CO2 (95/ 5) or tert-butyl hydroperoxide (TBHP). Loosely bound iron and glycogen conc entrations were also determined. The 4-day hearts exhibited more chemi luminescence after both oxygen and TBHP-driven stress. When exposed to O-2, they reached a maximum rate of chemiluminescence in one-third le ss time and exhibited a 22% higher count rate. Likewise, when stimulat ed by TBHP, their rate was 44% higher than the hearts of both older gr oups. The 4-day hearts also had a 40% greater content of loosely bound iron that may, in part, explain their greater susceptibility to oxida tive stress. Although the youngest hearts had the highest glycogen con tent, that did not offer protection against oxidative stress, as has b een previously reported for liver.