Intracellular adhesion molecule-1 expression and its correlation to pulmonary injury—a neonatal rat hyperoxic pulmonary injury model
WU Xia,LIU Guo-sheng,LUO Yao,SONG Wen-yuan. Department of Neonatology,First Affiliated Hospital,Jinan University,Guangzhou 510632,China
Objective To explore the expression of intracellular adhesion molecule-1(ICAM-1) during hyperoxic lung injury and to investigate the pathological changes of hyperoxia related pulmonary injury.Methods A total of 102 full term neonatal sprague-dawley rats were randomized into experimental(hyperoxia) and control(room air) groups of 51 rats each.Newborn rats in the experimental group were kept in boxes that contain 95% oxygen immediately after deliveries,whereas those in the control group were raised in room air instead.Rats from both groups were further randomized,three subgroups of eight rats from each group were chosen and sacrificed on the 3,7 and the 14 days of life subsequently.Extracted lung tissue was HE stained to reveal the gross pathological changes;Masson Trichrome Stain was used to observe the severity of pulmonary fibrosis;Immunohistochemical Semi-quantitative analysis of ICAM-1 was then performed.Results(1) Rats in the control group have no pathological change of pulmonary tissue at 3,7 and 14 days of age and no increased expression of collagen on Masson stain.There was negative to weak positive pulmonary ICAM-1 expression in the control rats.(2) In contrary,the rats which were raised in the hyperoxia environment from birth have shown significant inflammatory cell infiltration.Mild thickening of alveoli septum were also found in pulmonary tissue by day 7 post partum.By day 14,inflammatory cell infiltration began to subsidize,however,more prominent alveoli structural damage and marked thickening of alveoli septum were found.On Masson stain,increased collagen deposits began to present by day seven,prominent fibrosis was found by day 14.ICAM-1 expression was widely present in all subgroups of the experimental rats at the 3rd,7th and the 14th day of life.Semi-quantitative analysis revealed that the pulmonary ICAM-expression in rats of all the experimental subgroups were marked higher than the level in the corresponding control subgroups,with the peak expression at day 7 of life(P0.05).Conclusions High concentration oxygen exposure leads to prominent injury of lung tissue in neonatal rats.Shortly after birth,ICAM-1 expression elevates with increasing length of exposure to high concentration oxygen;however,ICAM-1 level gradually decreases with persistent usage of high concentration oxygen.Although the current study didn't reveal the correlation of ICAM-1 expression to hyperoxic pulmonary fibrosis,ICAM-1 is likely playing an active role in leukocyte adhesion to endothelium cells and in activation of cytokines during the acute inflammation phase of hyperoxic lung injury.
【CateGory Index】： R722.1