This study sought to determine whether
oxygen radical scavengers of
dimethylthiourea (
DMTU),
superoxide dismutase (SOD), or
catalase (CAT) pretreatment attenuated
ischemia-reperfusion (I/R)-induced
lung injury. After isolation from a Sprague-Dawley rat, the lungs were perfused through the pulmonary artery
cannula with rat whole blood diluted 1:1 with a physiological
salt solution. An
acute lung injury was induced by 10 minutes of
hypoxia with 5% CO2-95% N2 followed by 65 minutes of
ischemia and then 65 minutes of reperfusion. I/R significantly increased microvascular permeability as measured by the capillary filtration coefficient (Kfc), lung weight-to-
body weight ratio (LW/BW), and
protein concentration in bronchoalveolar lavage fluid (PCBAL).
DMTU pretreatment significantly attenuated the
acute lung injury. The capillary filtration coefficient (P<.01), LW/BW (P<.01) and PCBAL (P<.05) were significantly lower among the
DMTU-treated rats than hosts pretreated with SOD or CAT. The possible mechanisms of the protective effect of
DMTU in I/R-induced
lung injury may relate to the permeability of the agent allowing it to scavenge intracellular
hydroxyl radicals. However, whether
superoxide dismutase or
catalase antioxidants showed protective effects possibly due to their impermeability of the cell membrane not allowing scavenging of intracellular
oxygen radicals.