[Changes of FLI-1 protein expression in mice with pulmonary endothelial barrier dysfunction following acute lung injury induced by lipopolysaccharide].

Objective: To observe changes of Friend leukemia virus integration 1 (FLI-1) protein expression of pulmonary tissue in mice with pulmonary endothelial barrier dysfunction following acute lung injury (ALI) induced by lipopolysaccharide (LPS). Methods: The mouse model of ALI was established by injection of LPS (7.5 mg/kg, i.p. ). At 0 h, 12 h, 24 h and 48 h after LPS injection, pulmonary microvascular endothelial permeability and lung wet/dry weight ratio (W/D) were assessed. The contents of TNF-α and IL-6 in bronchoalveolar lavage fluid (BALF) were detected by ELISA method. The protein levels of FLI-1 and Src protein tyrosine kinase (SRC) were analyzed by Western blotting.Results: ①Pulmonary microvascular endothelial permeability at 12 h and 24 h were significantly higher than those of 0 h by 74.3% and 162.4%, respectively, while that of 48 h was lower than that of 24 h by 27.0% (P＜0.05). The W/D at 12 h and 24 h were significantly higher than those of 0 h by 50.1% and 122.9%, respectively, while that of 48 h was lower than that of 24 h by 10.7% (P＜0.05). ②The contents of IL-6 and TNF-α in BALF at 12 h and 24 h were significantly higher than those of 0 h, while those of 48 h were significantly lower than those of 24 h by 28.3% and 21.6% (P＜0.05), respectively. ③The protein level of FLI-1 in lung at 12 h and 24 h were down-regulated than those of 0 h by 20.4% and 56.9%, respectively, while that of 48 h was up-regulated than that of 24 h by 18.2% (P＜0.05). The protein level of SRC in lung at 12 h and 24 h were up-regulated than those of 0 h by 76.8% and 176.7%, respectively, while that of 48 h was down-regulated than that of 24 h by 33.4% (P＜0.05).④Same as the protein level of FLI-1 with the protein level of SRC in lung, pulmonary microvascular endothelial permeability was significantly negative correlated with the protein level of FLI-1 in lung, while it was significantly positive correlated with the protein level of SRC (P＜0.01). Conclusion: FLI-1 participates in the pathological proceeding of pulmonary endothelial barrier dysfunction following ALI induced by LPS.

[Effects of apolipoprotein E on proliferation of mouse pulmonary arterial smooth muscle cells induced by hypoxia].

OBJECTIVE: To investigate the effects of apolipoprotein E (apoE) on the proliferation of pulmonary arterial smooth muscle cells (PASMCs) induced by hypoxia. METHODS: Primary culture of mouse PASMCs was prepared from male C57BL/6 mouse pulmonary artery by the method of tissue block anchorage. PASMCs were divided into four groups: normoxia group, normoxia with apoE administration group, hypoxia group and hypoxia with apoE administration group. The proliferation of PASMCs was observed by EdU incorporation. The protein levels of apoE, proliferating cell nuclear antigen (PCNA), protein kinase C (PKC) and phosphorylated protein kinase C (p-PKC) were analyzed by Western blot. RESULTS: The percentage of PASMCs proliferation of hypoxia group was significantly higher than that of normoxia group by 64.7% (P＜0.05), and the protein expression levels of PCNA and p-PKC of hypoxia group were up-regulated than those of normoxia group by 69.0% and 120.0%, while the protein expression of apoE was down-regulated by 51.0% (P＜0.05), respectively. The percentage of PASMCs proliferation of hypoxia with apoE administration group was significantly lower than that of hypoxia group by 19.6% (P＜0.05), and the protein expression levels of PCNA and p-PKC of hypoxia with apoE administration group were down-regulated than those of hypoxia group by 19.8% and 103.2% (P＜0.05), respectively. There was no significant difference among each group in the protein expression of PKC, nor do there any significant difference between normoxia group and hypoxia group in the protein expression of p-PKC (P＞0.05). CONCLUSION: ApoE can inhibit the proliferation of PASMCs induced by hypoxia, and the mechanism of its effect may be attributed to blocking PKC pathway.

[Changes of apoE protein expression in lung of mice with hypoxic pulmonary arterial hypertension].

OBJECTIVE: To observe the changes of apolipoprotein E (apoE) protein expression of pulmonary tissue in mice with pulmonary hypertension induced by hypoxia. METHODS: The animal model of hypoxic pulmonary hypertension was established by exposing the mice to isobaric hypoxic chamber for 3 weeks (23 h/d, regular chow feed).Twenty male wild type (WT) C57BL/6 mice and twenty apoE gene knockout (apoE-KO) mice were randomly divided into normoxia group and hypoxia group. The plasma concentrations of low density lipoprotein (LDL), high density lipoprotein (HDL) and total cholesterol were detected by ELISA method. The protein expression of apoE in lung and liver, and peroxisome proliferators-activated receptor gamma (PPARγ) in lung were measured by Western blot. RESULTS: ①In WT mice, the right ventricular systolic pressure (RVSP) and the weight ratio of right ventricle (RV) to left ventricle plus septum (LV+S) of hypoxia group were significantly higher than those of normoxia group by 68% and 59% (P<0.05), respectively. The plasma concentration of HDL and HDL/LDL of hypoxia group were significantly lower than those of normoxia group by 17% and 40% (P<0.05), respectively.The protein expression of apoE in lung and in liver of hypoxia group were significantly down-regulated than those of normoxia group by 48% and 52% (P<0.05), respectively.The protein expression of PPARγ in lung was significantly down-regulated than that of normoxia group by 37%(P<0.05).RVSP were significantly negative correlated with the protein levels of apoE and PPARγ in lung (P<0.01).② In apoE-KO mice, RVSP and the weight ratio of RV to LV+S of hypoxia group were significantly higher than those of normoxia group by 96% and 86% (P<0.05), respectively.RVSP and RV to (LV+S) of hypoxia group in apoE-KO mice were significantly higher than those of hypoxia group in WT mice by 29% and 24% (P<0.05), respectively. CONCLUSIONS: Down-regulated expression of apoE in lung tissue participates in the pathological proceeding of pulmonary hypertension induced by hypoxia.