Burn and smoke inhalation injury in sheep depletes vitamin E: Kinetic studies using deuterated tocopherols

To test the hypothesis that burn and smoke injury will deplete tissue α-tocopherol and cause its faster plasma disappearance, deuterium-labeled vitamin E was administered to sheep exposed to both surface skin burn and smoke insufflation, which cause injuries similar to those of human victims of fire accidents. Two different protocols were used: (1) deuterated vitamin E was administered orally with food at time 0 (just before injury) or (2) the labeled vitamin E was administered orally with food the day before injury. The animals, which had been operatively prepared seven days before, were anesthetized and then received both 40% body surface area third-degree burn and 48 breaths of cotton smoke or sham injuries. All were resuscitated with Ringer's lactate solution (4 ml/kg/% BSA burn/24 h) and mechanically ventilated. Blood samples were collected at various times after vitamin E dosing. In both studies the depletion of plasma α-tocopherol was faster in the injured sheep. The sheep given deuterated vitamin E 24 h before injury had similar maximum α-tocopherol concentrations at similar times. The exponential rates of α-tocopherol disappearance were 1.5 times greater and half-lives were 12 h shorter (p < 0.05) in the injured sheep. In separate studies, various tissues were obtained from sheep that were sacrificed from 4 to 48 h after injury. The liver α-tocopherol concentrations in sheep killed at various times after injury seem to show a linear decrease at a rate of 0.1 nmol α-tocopherol/g liver per hour, suggesting that the liver is supplying α-tocopherol to maintain the plasma and lung α-tocopherol concentrations, but that this injury is so severe the liver is unable to maintain lung α-tocopherol concentrations. These findings suggest that α-tocopherol should be administered to burn patients to prevent vitamin E depletion and to protect against oxidative stress from burn injury.