The Effects Of Systemic Perfluorocarbon On LPS-induced Acute Lung Injury

Perfluorocarbons (PFCs) have been used in ALI/ARDS treatment by liquid ventilation and aerosol or vapor inhalation and revealed its extensive biological effects such as surfactant-like and nonspecific antiinflammatory effects. These suggest that systemic administration may have therapeutic effects on ALI/ARDS. In this study, with animal model of LPS-induced lung injury, we made researchs on the effects of systemic PFC on acute lung injury in three parts:Objectives1.To explore the feasibility of systemic application through peritoneum and vein;2.To investigate the therapeutic and antiinflammatory effects of PFC (PFO) injected intraperitoneally and PFCE (PFTE or PFT) injected intravenously on acute lung injury.Methods1. In the exploration of feasibility, Wistar rats grouped by timepoint in four treatment groups were intraperitoneally injected with PFO (15ml/Kg) and in eight treatment groups were intravenously administrated with PFTE (10ml/Kg); control groups with normal saline. The animals were exsanguinated and sampled for measurment of arterial blood gas analysis, liver and kidney function, blood concentrations of PFC and absorption rate of PFO. The tissue of lung, liver and kidney were histologically assessed.2. In the research on therapeutic and antiinflammatory effects of PFO, the animals were divided into two treatment groups(LPS and LPS+PFO) and two control groups(NC and PFO). The rats were intraperitoneally injected with PFO (15ml/Kg) in PFO group and LPS+PFO group, with normal saline in others at 48 hours before experiment; received LPS (7mg/Kg) to induced lung injury in treatment groups and normal saline in controls at experiment hour. At 2h, 4h and 6h timepoints, the animals were exsanguinated and sampled for measurements of PaO2, lung index (LI), lung permeability index(LPI) and lung histologic examination in therapeutic effect study. The animals were sampled for counts of WBC and PMN in blood and BALF, and PMN in lung tissue, measurements of IL-1βand TNFαin serum and BALF, the expression(IOD) of E-selectin, ICAM-1 and NF-κB measured immunohistochemically in antiinflammatory study.3. In the research on therapeutic effects and antiinflammation of PFT, the animals divided into two treatment groups(LPS and LPS+PFT) and two control groups(NC and PFT)were injected via penile vein with PFT (10ml/Kg) in PFT group and LPS+PFT group, with normal saline in others. Five minutes late, the animals received LPS (7mg/Kg) to induced lung injury in treatment groups and normal saline in controls. At 2h, 4h and 6h timepoints, the rats were exsanguinated and sampled for measurements of PaO2, the ratio of wet and dry weight of lung (W/D), lung permeability index(LPI) and lung histologic examination in therapeutic effect study. The animals were sampled for counts of WBC and PMN in blood and BALF, PMN in lung tissue, measurements of IL-1βand TNFαin serum and BALF, the expression (MFI) of CD11b on PMN measured with Flow cytometry and the expression (IOD) of E-selectin, ICAM-1 and NF-κB measured immunohistochemically in antiinflammatory study.Results1. The absorption rate of PFO intraperitoneally administrated was to 0.93±0.03 at 72h. The blood concentration of PFO reached highest (1.67±0.30 ug/ml) at 48h and cannot detected 1 month late. There were no effects on the liver and kidney function. After PFTE intravenously administrated, its blood concentration was highest (3229.34±466.01ug/ml) at 1h and rapidly reduced to 349.9±88.61ug/ml at 6h and cannot detected 10 days late. The PaO2 significantly increased (p<0.01), but rapidly decreased to the level of no significant difference (p>0.05) compared with control group at 6h timepoint. The levels of ALT and AST also significantly increased (p<0.01) and decreased to the level of control group (p>0.05) at tenth day.2. The results of therapeutic effects of PFO showed that the LPS significantly reduced PaO2 compared with NC, PFO increased PaO2 compared with LPS but significantly only at 6h timepoint (p<0.05). LI and LPI were significantly reduced in LPS+PFO group compared with LPS group at 4h and 6h timepoints (p<0.05 or 0.01). The edema and infiltration of leukocytes in lung tissue slightly reduced in PFO group. The results of antiinflammation of PFO showed that LPS significantly increased the counts of WBC and PMN in BALF and PMN in lung tissue at all timepoints and WBC in blood at 2h timepoint, decreased these of WBC in blood at 6h timepoint and PMN in blood at three timepoints compared with NC (p<0.01). The PFO significantly inhabited the effects of LPS (p<0.01). The levels of IL-1βand TNFαin serum and BALF markedly increased in LPS group than in normal controls (p<0.01or 0.05) and significantly decreased in LPS+PFO group, when compared with LPS group (p<0.01) except in 2h and 4h timepoint for TNFαin serum. The expression(IOD) of E-selectin, ICAM-1 and NF-κb significantly reduced in LPS+PFO group than in LPS group(p<0.01).3. The results of therapeutic effects of PFT showed that PaO2 significantly decreased in LPS group than in controls (P<0.01) and increased in PFT and LPS+PFT groups compared with LPS group (p<0.01). W/D and LPI were significantly lower in LPS+PFT group than in LPS group at 4h and 6h timepoints (p<0.05 and 0.01).The edema and infiltration of leukocytes in lung tissue markedly reduced by PFT. Alveolar inflation and foam granules of PFC were found histologically in PFT and LPS+PFT groups.The results of antiinflammation of PFT showed that LPS significantly increased the counts of WBC and PMN in BALF and PMN in lung tissue at all timepoints and WBC in blood at 2h timepoint, decreased these of WBC in blood at 6h timepoint and PMN in blood at three timepoints compared with controls(p<0.01). The PFT significantly inhabited these effects of LPS (p<0.01). The levels of IL-1βand TNFαin serum and BALF markedly increased in LPS group than controls (p<0.01) and decreased in LPS+PFT group compared with LPS group (p<0.01 or 0.05). The expression(MFI) of CD11b on PMN and the expression (IOD) of E-selectin, ICAM-1, NF-κb significantly reduced in LPS+PFT group than in LPS group(p<0.01).Conclusions1. The systemic application of PFC through peritoneum(PFO) and vein(PFTE) can reach certain blood concentrations of PFC and maintain some hours. PFO has no toxicity on liver and kidney function. Thus, the way of systemic application of PFC is safe and feasible.2. PFO administrated intraperitoneally and PFT injected intravenously increase PaO2, decrease lung edema, permeability. Furthermore, PFT may improve the pathological changes of lung. These suggest that systemic application of PFO and PFT may have therapeutic effects on LPS-induced acute lung injury.3. Systemic PFO and PFT inhabit the lung infiltration of PMN, reduce the release of proinflammatory cytokine. These suggest that systemic PFO and PFT may have significant effects of nonspecific antiinflammation on LPS-induced aute lung injury, which may be correlated with the prohibition of the expession of E-selectin, ICAM-1, NF-kb and CD11b.