The influence of inhaled liposomes, containing dipalmitoyl phosphatidylcholine and a-tocopherol, and liposomes containing dipalmitoyl phosphatidylcholine, retinol and retinoic acid, on parameters of the oxidantantioxidant system in lungs of newborn guinea pigs exposed to hyperoxia during 3 and 14 days has been studied. Administration of both types of liposomes under conditions of prolonged hyperoxia (14 days) results in normalization of glutathione peroxidase activity and prevents elevation of the levels of lipid and protein peroxidation products in bronchoalveolar lavage fluid. Unlike liposomes with a-tocopherol, administration of liposomes containing retinoids did not cause the normalizing effect on the content of nonprotein SH-compounds in the bronchoalveolar fluid and contributed to significant reduction of the a-tocopherol level in lung tissues.

Morphological basis of lung injury by free radicals and the treatment in newborn guinea pigs SummaryStructural and morphometrical lung changes in guinea pigs exposed to hyperoxia or induced reactive oxygen species (ROS) production during 14 days alone or under inhalations of N acetylcysteine (in water solution or built in multilayered liposomes), α tocopherol or retinol have been stud ied. We established that induced ROS production in the lungs was associated with structural change of the lung tissue compatible with that in ani mals exposed to hyperoxia. Most typical changes associated with hyperoxia and induced ROS production were reduction in the alveolar intercept area and increase in the total area of the alveolar space and intrapulmonary vessel lumen. All the therapy regimens effectively prevented hyperoxia induced changes of the alveolar space / interstitium relationship but were fail to prevent the dilation of the intrapulmonary vessels. The inhalation of N acetylcysteine seemed to be the most effective treatment.

Oxidative stress is considered to be a factor leading to lung damage in premature infants. The aim of this study was to investigate the effect of inhaled antioxidants incorporated into egg lecithin liposomes on the indicators of oxidative stress in the lungs of newborn guinea pigs under experimental hyperoxia (3 days). Bronchoalveolar lavage fl uid (BALF) was used as a material for the study. Under hyperoxia exposure, inhalation of liposomes containing N-acetylcysteine and alpha-tocopherol contributed to the suppression of the reactive oxygen species production by cells, normalization of glutathione peroxidase activity and carbonyls content, while not affecting the level of diene conjugates in BALF. The introduction of retinoid-containing liposomes (retinol and retinoic acid) under hyperoxia was accompanied by normalization of glutathione peroxidase activity as well as the content of protein oxidation products in BALF, while the generation of reactive oxygen species remained enhanced, and the diene conjugates and thiobarbituric acid reactive products exceeded the levels in animals exposed to hyperoxia alone. Thus, the inhaled liposomes containing retinoids and egg lecithin exhibit not only anti-, but also a prooxidant effect in the lungs under hyperoxia exposure, unlike the liposomal forms of N-acetylcysteine and alpha-tocopherol.