Antioxidant enzymes and lipid peroxidation in cold ischemic lung preservation.
Our purpose was to investigate antioxidant enzymes and lipid peroxidation in time course ischemic lung preservation in rats. Thirty-six Wistar rats were divided into 6 groups of 6 rats each. After having been anesthetized, the rats were intubated and connected to a rodent ventilator. Lung-heart blocks were excised. In the control group, the lungs were immediately stored at -80 degrees C after removal. The lungs from the other groups were preserved in 40 mililiters of low potassium dextran solution at 4 degrees C for 6, 12, 24, 48, and 72 hours, respectively. Antioxidant enzyme activity and malondialdehyde levels were then measured. Superoxide dismutase activity significantly increased at the 12th hour and remained higher up to the 72nd hour (P < .001). Glutathione peroxidase activity was higher than that in the control group from the 6th to the 24th hour but was significant only at the 12th hour (P < .001) and decreased below the level in the control group after the 48th hour. Catalase activity was significantly higher than that in the control group in all preservation periods (P < .001). The nitric oxide level slowly increased and reached a significantly higher level than that in the control group at the 24th and 72nd hours (P = .028) and then decreased to the level found in the control group. The malondialdehyde level slightly increased from the 6th to the 24th hour, but that increase, when compared with the level in the control group, had no statistical significance (P = .110). In ischemic lung preservation, oxidative stress begins during the early phase of preservation and continues for up to 72 hours. Although oxidative stress continues for a significant period, an antioxidant mechanism adequately prevents its harmful effects on the lung. Thus no significant lipid peroxidation occurred in long-term ischemic lung preservation in the murine model studied.