Objective To investigate the effect of aerosolized perfluorocarbon (PFC) (FC77) on gas exchange，histopathological changes of lung in acute lung injury and pulmonary expression of tumor necrosis factor-α (TNF-α) mRNA.Methods After acute lung injury (ALI) was induced by oleic acid (OA)，16 rabbits were assigned randomly into 2 groups,ie.aerosolized perfluorocarbon group (PFC group) and conventional mechanical ventilation group (CMV group).Gas exchange parameters were measured before and after ALI，at 1，2，3，4 h after treatment.Histological sections taken from 6 different parts of lung were stained by hematoxylin and eosion.The express of TNF-α mRNA in the 2 different parts of lung were detected by in situ hybridization (ISH).Results Compared with CMV group，the PaO2 and static lung compliance (CLst) were significantly increased (Plt;0.05)，the histopathological lesions of lung were attenuated，and the TNF-α mRNA expression was decreased significantly in PFC group (all Plt;0.05).There was more expression of TNF-α mRNA in backside than that in foreside of lung in two groups (Plt;0.05).Conclusion Aerosolized perfluorocarbon (PFC) can decrease expression of tumor necrosis factor-α mRNA in the lung，and improve the CLst and oxygenation during acute lung injury.
Objective To investigate whether P12，a kind of lipopolysaccharide（LPS）-binding protein（LBP） inhibitory peptide，could suppress the binding of LPS to alveolar macrophages（AMs） in a mouse model of endotoxemia in vivo.Methods Forty mice were randomly divided into five groups，ie.a control group，an endotoxemia group，a low dose P12-treated group，a middle dose P12-treated group and a high dose P12-treated group.Mouse model of endotoxemia was established by LPS injection intraperitoneally in the endotoxemia group and P12-treated groups.P12 was instilled via the tail vein.The effects of P12 on the binding of LPS to AMs were determined by flow cytometric analysis and quantization by mean fluorescence intensity(MFI).The productions of tumor necrosis factor α(TNF-α) in serum of mice were measured by enzyme-linked immunosorbent assay(ELISA).Results MFI in AMs from low，middle and high dose P12-treated groups was 40.08%，30.76% and 24.45%，respectively，which was higher than that of the control group(4.61%)，but less than that of the endotoxemic mice(45.31%).The concentration of TNF-α in serum of low，media and high dose P12-treated mice was (112.69±19.78)pg/mL，(86.34±9.25) pg/mL，(70.48±8.48)pg/mL respectively，which was higher than that of the control group[(24.88±5.82)pg/mL]，but less than that of the endotoxemic mice[(180.17±39.14)pg/mL].Conclusion The results suggest that P12 inhibit the binding of LPS and AMs，thus reduce the proudction of TNF-α stimulated by LPS.
Objective To compare the in vitro inhibition activity of three mimic peptides at lipopolysaccharide binding protein (LBP)／CD14 binding sites for LPS-induced inflammatory response.Methods Enzyme-linked immunoSorbent assay(ELISA)was applied for the detection of the affinity between the mimic peptides and CD14 as well as the competitive inhibition activity of LBP.Mature U937 cells induced by PMA were co-cultured with LPS and intervened by mimic peptide.The effect of the mimic peptide on the TNF-α expression of U937 was detected by RT-PCR.Alveolar macrophages(AMs)of rats were co-cultured with FITC-LPS，and mimic peptide intervention was conducted.The effect of the mimic peptide on combination of LPS and AMs was observed by fluorescence microscope . Results Affinity between No.1 mimic peptide(FHRWPTWPLPSP，10 μg／mL)and CD14 was significantly higher than those of No.2 and No.3(20.3±4.1 11.8±2.4 and 13.7±3.3，Plt;0.01 or Plt;0.05).The competitive inhibitory activity of No.1 mimic peptide(10 μg／mL)for LBP was higher than those of No.2 and No.3[(57.2土11.2)％ vs(39.4±9.7)％ and(37.9±8.3)％ ，Plt;0.01].All of the three mimic peptides(10 μg／mL)could significantly inhibit the LPS-induced expression of TNF-α by U937 at mRNA level(Plt;0.01 or Plt;0.05)，moreover，the inhibitory activity of No.1 peptide was the highest(0.239±0.053 vs 0.406±0.112 and 0.493±0.121，Plt;0.01).In addition，No.1 mimic peptide markedly inhibited LPS combination with rat lung AMs(2157±514 vs 2763±453，plt;0.01).Conclusion No.1 mimic peptide(FHRWPTWPLPSP)have a relatively higher affinity with CD14 and high competitive inhibition activity for LBP，therefore it have the potential ability of anti-inflammatory response induced by LPS.