ALPHA-TOCOPHEROL ATTENUATES LUNG EDEMA AND LIPID-PEROXIDATION CAUSED BY ACUTE ZYMOSAN-INDUCED PERITONITIS

Background. Inflammation-induced disease as seen with trauma and infection can lead to increased lung oxidant activity resulting in cell membrane lipid peroxidation. Acute zymosan-induced peritonitis in rats produces lung inflammation, edema, and lipid peroxidation. We determined whether administered alpha-tocopherol (vitamin E), the key antioxidant protection against cell membrane lipid peroxidation, would improve this process. Methods. Male Wistar rats were given 0.75 mg/kg of intraperitoneal zymasan, volume resuscitated, monitored, and killed at 4 or 24 hours. Lung histologic changes and levels of conjugated dienes, a marker of lipid peroxidation, were used to monitor injury. The levels of vitamin E, vitamin C, and catalase were used to monitor antioxidant defenses. The effect of administering alpha-tocopherol (50 mg/kg) by gauge immediately after zymosan on the degree of the lung injury was then determined. Results. Twenty-four hours after zymosan was administered, the vitamin E levels in plasma were significantly decreased, but lung tissue vitamin E levels were maintained, whereas tissue catalase and vitamin E levels decreased. Lung tissue-conjugated diene levels, alveolar edema, and neutrophil count were significantly increased, alpha-Tocopherol treatment increased the postzymasan plasma vitamin E levels by 50%. Lung tissue vitamin E levels did not increase; however, the degree of lung injury and lipid peroxidation was significantly attenuated. Tissue catalase levels were also maintained. Conclusions. We conclude that alpha-tocopherol given at the onset of a progressing inflammatory injury can protect the lung from oxidant damage and attenuate the degree of lung injury.