ABSTRACT
Objective To investigate the effects of therapeutic hypercapnia on type Ⅱ alveolar cells (ATⅡ ) in the transplanted lung in rats.Methods Twenty-eight pathogen free adult male Wistar rats weighing 180-220 g were randomly divided into 2 groups (n= 14 each) : control group (group C) and therapeutic hypercapnia group (group T). The animals were anesthetized with intraperitoneal 3% pentobarbital 30 mg/kg, tracheostomized and mechanically ventilated with 50% O2-50% N2 (VT 10 ml/kg, RR 60 bpm, I∶ E1∶1). Left lung transplantation was performed. In group T starting from the beginning of reperiusion of the transplanted lung, the animals were ventilated with a mixture of 50% O2-N2 and C02(in appropriate concentrations) to keep PaCO2 between 80-100 mm Hg. After 90 min of reperfusion of the transplanted lung, blood samples were collected from pulmonary vein of the transplanted lung and blood gas analysis was performed. Oxygenation index was calculated.AT II cells were isolated from the transplanted lung and purified and examined with electronic microscope. The apoptosis rate of AT Ⅱ cells was detected by flow cytometry. Results Oxygenation index was significantly higher, the apoptotic rate of ATⅡ cells lower, the damage to ATⅡ cells was less in group T than in group C.Conclusion Therapeutic hypercapnia can protect the AT Ⅱ cells in the transplanted lung and improve the function of the trans planted lung.
ABSTRACT
Objective To investigate the effect of therapeutic hypercapnia on the inflammatory response in the rat lung transplantation. Methods Male pathogen free Wistar rats weighing 300-400 g were used in this study. The animals were anesthetized with 3% pentobarbital sodium 30 mg/kg, tracheostomized and mechanically ventilated (V_T 10 ml/kg, RR 50 bpm, FiO_2 50%). Carotid artery and femoral vein were cannulated for BP monitoring, blood sampling and fluid and drug administration. Left lung transplantation was performed using modified cuff technique. Forty-eight animals in which lung transplantation was successfully performed were randomized into 2 groups ( n = 24 each) : model group (M) and hypercapnia group (H) . In group H, PaCO_2 was maintained at 80-100 mm Hg by inhalation of CO_2.Arterial blood samples were obtained before lung transplantation (To , baseline) and at 1, 2, 4 h (T_(1-3)) of reperfusion for determination of blood TNF-α, IL-1 and IL-8 concentrations. The animals were then killed and the transplanted lungs were removed for microscopic examination and calculation of wet/dry lung weight ratio. Results The MAP and PaO_2 were significantly higher in group H than in group M. The blood IL-8 and TNF-α concentrations were significantly lower at T_(1-3) in group H than in group M, but there was no significant difference in blood IL-1 concentration between the 2 groups. The elastase content in the lung tissue was significantly lower at T_2 and T_3 in group H than in group M. Microscopic examination showed that the alveolar hemorrhage, the infiltration of the lung by macrophages and neutrophils and lung edema were significantly less in group H than in group M. Conclusion Therapeutic hypercapnia can obviously inhibit the inflammatory response in the rat lung transplantation.
ABSTRACT
Objective T Iymphocytes were considered to be activated and involved in the ischemia-reperfusion injury during lung transplantation.Carbon dioxide pneumoperitoneum was shown to have inhibitory activity on the immune system.This study was designed to_investigate the effects of the effects of the therapeutic hypercapnia on the T Iymphocytes of rats in which ischemia-reperfusion injury occurred during lung transplantation.Melhods Sixteen Wismr rats weighed 300 to 400 g were randomized into control group(8 rats) or therapeutic group (8 ras)after transplantaion.Animals in both grotups were Oven inluded nitrogen(50%)and oxygen N2+(50%) at baseline. Animats in the control groap were given irked nitrogen (50%)and oxygen(50%)throughout the experiment ,and that in the thera-peutic group were given mixed gas which was composed of nitroged(40%),oxygen(60%)and carbon dioxide in appropriate concentra-tion to keep arterial partial pressure of carbon dioxide (PaCO2)at 80-100 mm Hg and FiO2 at 50%after reperfusion.All of the ani-mals were observed for 90 minutes after reperfusion.Mean arterial pressure(MAP) and arterila partial pressure of oxygen(PaO2) were recorded at baseline and every 15 minutes during the period of reperfusion.The expression of CD3,CD4 and CD28 in the peripheral blood was,examined,and the concentrations of Ifn-у,IL-2,IL-4 and IL-1O in the homogenate were measured after the experiment. Histological analysis of samples from transplanted lungs was performed.Resykts After reoerfysion,MAP and PaO2 in the therapeutic group were higher signitleantly than that in the group(P<O.05).The expression of CD3,CD4 and CI)28 in the perioheral blood,mid the concentrations of IL-2 and IFN-y in the homogenate higher sinificantly in the group than that in the thera- peutic group (for all comparisons,P<O.05).IL-4 was decreased in the control group as compared with the therapeutic group(P<0.05).No sigllificant difference for IL-IO was observed between two groups.Histological study revealed that the haemorrhage and edema were obviously alleviated in the therapeutic group.Conclusion Therapeutic lypercapnia may have inhibitory effects on the T Iymppho- cytes in rats receiving lung transplantation.This treatment decreaseed the number of T lymphocytes in the peripheral blood and the expres-sion of CD28,as well as IL-2 and IFN-y secreted by the Thl cells,and facukutated IL-4 production by Th2 cells.