The Study Of The Protective Effect Of Dexmedetomidine On Lung Ischemia-Reperfusion Injury Of Rat

Objective:To investigate the protective effect of dexmedetomidine in rat lung ischemia-reperfusion model.Methods:SD rats were randomly separated into5groups (n=18):①Sham control group:0.9%sodium chloride injection (3mL/kg-d) for intraperitoneal injection for2d,30min after d2, the thoracotomy free was done, without clamping,②Ischemia-reperfusion model group:0.9%sodium chloride injection (3mL/kg-d) injected intraperitoneally for2d,③Dexmedetomidine low dose group:100μg/kg-d intraperitoneal injection for2d,④Dexmedetomidine high dose group:500μg/kg-d intraperitoneal injection for2d,⑤Shenfu injection group:0.8mL/kg-d intraperitoneal injection for2d.②-⑤groups were underwent the preparation of lung ischemia and reperfusion model after30min of administration on d2.Lung Wet/dry by weighing, plasma MDA (malondialdehyde)by thiobarbituric acid assay, plasma MPO (Myeloperoxidase), TNF-α (Tumor Necrosis Factor-α)in lung tissue, total protein (TP) concentration in bronchoalveolar lavage fluid(BALF), lung injury by HE method were tested in rats of the three time points:ischemia45min,60min and120min after reperfusion, respectively.Results:Lung W/D ratio, MPO, TNF-a and SOD had no significant differences (P>0.05) when ischemia45min in model and dexmedetomidine groups.Compared with model, lung W/D ratios in dexmedetomidine high dose group were lower after reperfusion60min and120min TNF-a in dexmedetomidine high dose group ischemia45min after reperfusion60min, after reperfusion120min were lower. TNF-a in dexmedetomidine low dose group were lower after reperfusion120min. MPO in lung of dexmedetomidine low dose group and high dose groupwere lower after reperfusion60min. MPO in lung of dexmedetomidine high dose group were lower after reperfusion120min.SOD in dexmedetomidine lowand high dose group had no significant changes after reperfusion60min and120min, respectively. MDA in dexmedetomidine low and high dose group were lower after reperfusion60min and120min, respectively.MPO were lower in dexmedetomidine low and high dose group were lower after reperfusion60min. MPO were lower in dexmedetomidine high dose group after reperfusion120min.Compared with the model group, degree of alveolar damage in dexmedetomidine low dose group and high dose group were significantly lower. TP in dexmedetomidine high dose group were hsignificantly lower. The control group showed alveolar destruction signs of structural integrity, visible organizations alveolar wall integrity, no interstitial lung edema and neutrophil infiltration. Model group showed alveolar structure severely damaged, a large number of alveoli and alveolar wall congestion, consolidation, severe thickening of the pulmonary interval, severe alveolar spaces and interstitial edema and serous effusion, and a large number of red blood cells and neutrophil infiltration were seen. The extent of the damage of cell structure of alveolar, interstitial neutrophils and red blood cells were less in dexmedetomidine low dose group Lung tissue change in dexmedetomidine high dose group were between the dexmedetomidine low dose group and control group.Conclusion:Dexmedetomidine has a potential protective effect on lung ischemia reperfusion injury and could be used on acute lung injury in intensive care patients.