[Expression of thrombospondin-1 in the lung of hypoxic pulmonary hypertension rats].

OBJECTIVE: To investigate the expression of thrombospondin-1(TSP-1) in the lung of hypoxia-induced pulmonary hypertension rats. METHODS: Thirty male Wistar rats were divided into two groups, pulmonary hypertension group and control group. The mice in experimental group were exposed to isobaric hypoxia for 3 weeks, and those in control group were exposed to air. The pulmonary artery pressure was measured by right cardiac catheterization. The expression of TSP-1 and TGF-beta1 in the lungs of rats were measured by immunohistochemical staining. The histological sections of the lungs were examined using a computerized image analyzer. RESULTS: After the induction of hypoxia for 3 weeks, the rats had pulmonary artery pressure increased with the thickening of the wall and the narrowing of the lumen of pulmonary arterioles. In the experimental group, the mean pulmonary artery pressure (mPAP) was (2.86 +/- 0.39) kPa, the index of right ventricular hypertrophy RV/(LV+S) was (43.53 +/- 3.38)%, the ratio of vascular wall thickness/vascular external diameter (WA%) was (55.09 +/- 12.38)%, and the ratio of vascular wall area/total vascular area (WT%) was (35.24 +/- 11.2)%, which all were significantly increased in comparison with those of control group [mPAP (1.35 +/- 0.28) kPa, RV/(LV+S) (23.68 +/- 3.48)%, WT% (23.63 +/- 9.74)%, WA% (41.62 +/- 12.83)%, respectively. P < 0.05). The positive staining of TSP-1 (1.32 +/- 0.04 vs. 0.96 +/- 0.03) and TGF-beta1 (1.38 +/- 0.05 vs. 1.04 +/- 0.04) in the wall of pulmonary arteriole of the rats exposed to hypoxia were significantly stronger than those of control rats (P < 0.01). CONCLUSION: The expression of TSP-1 appears to be increased in hypoxic pulmonary hypertension rats, which may contribute to the pathogenesis of hypoxic pulmonary vascular remodeling.

[The expression of thrombospondin-1 in serum and pulmonary arterioles of hypoxic pulmonary hypertension rats].

OBJECTIVE: To investigate the expression of thrombospondin-1 (TSP-1) in serum and pulmonary arterioles of rats with hypoxic pulmonary hypertension. METHODS: Twenty male Wistar rats were divided into two groups and exposed to air and isobaric hypoxia for 3 weeks respectively. The mean pulmonary artery pressure (mPAP) was measured by right cardiac catheterization. The rates of wall thickness/external diameter (WT%) and wall area/total vascular area (WA%) were calculated. The TSP-1 level in serum was measured by enzyme-linked immunosorbent assay. TSP-1 mRNA expression in lung tissue was evaluated by quantitative PCR. RESULTS: The pulmonary artery pressure increased in the hypoxia exposed rats. The chronic hypoxia also elicited the thicking of the wall and the narrowing of the lumen of pulmonary arterioles. It led to the increases of pulmonary artery pressure, the index of right ventricular hypertrophy [RV/(LV+S)], WA% and WT% compared to the controls [mPAP:(2.86 +/- 0.39) kPa vs. (1.35 +/- 40.28) kPa; RV/(LV+ S): (43.53 +/- 3.38)% vs. (23.68 +/- 3.48)%; WT%: (35.24 +/- 11.20)% vs. (23.63 +/- 9.74)%; WA%: (55.09 +/- 12.38)% vs. (41.62 +/- 12.83)% respectively, P<0.05]. In hypoxic group, the expression of TSP-1 mRNA in the lung was significantly up-regulated, the expression level of TSP-1 in serum was higher than that in control group (P<0.01). Linear correlation analysis showed that TSP-1 mRNA was positively associated with WT%, WA% and mPAP (r= 0.748, 0.686, 0.942 respectively, P<0.05). CONCLUSION: The TSP-1 may play an important role in the pathogenesis process of hypoxic pulmonary vascular remodeling and pulmonary hypertension.

Tyrosine sulfation in N-terminal domain of human C5a receptor is necessary for binding of chemotaxis inhibitory protein of Staphylococcus aureus.

AIM: Staphylococcus aureus evades host defense through releasing several virulence proteins, such as chemotaxis inhibitory protein of staphylococcus aureus (CHIPS). It has been shown that extracellular N terminus of C5a receptor (C5aR) forms the binding domain for CHIPS, and tyrosine sulfation is emerging as a key factor in determining protein-protein interaction. The aim of this study was to evaluate the role of tyrosine sulfation of N-terminal of C5aR in its binding with CHIPS. METHODS: Expression plasmids encoding C5aR and its mutants were prepared using PCR and site-directed mutagenesis and were used to transfect HEK 293T cells using calcium phosphate. Recombinant CHIPS protein was purified. Western blotting was used to examine the binding efficiency of CHIPS to C5aR or its mutants. RESULTS: CHIPS exclusively binds to C5aR, but not to C5L2 or C3aR. A nonspecific sulfation inhibitor, sodium chlorate (50 nmol/L), diminishes the binding ability of C5aR with CHIPS. Blocking sulfation by mutation of tyrosine to phenylalanine at positions 11 and 14 of C5aR N terminus, which blocked sulfation, completely abrogates CHIPS binding. When tyrosine 14 alone was mutated to phenylalanine, the binding efficiency of recombinant CHIPS was substantially decreased. CONCLUSION: The results demonstrate a structural basis of C5aR-CHIPS association, in which tyrosine sulfation of N-terminal C5aR plays an important role. Our data may have potential significance in development of novel drugs for therapeutic intervention.

[Effects of exogenous spermidine on lipid peroxidation and membrane proton pump activity of cucumber seedling leaves under high temperature stress].

Taking a relatively heat-resistant cucumber (Cucumis sativus) cultivar 'Jinchun No. 4' as test material, a sand culture experiment was conducted in growth chamber to investigate the effects of foliar spraying spermidine (Spd) on the lipid peroxidation, membrane proton pump activity, and corresponding gene expression of cucumber seedling leaves under high temperature stress. Compared with the control, foliar spraying Spd increased the plant height, stem diameter, dry and fresh mass, and leaf area significantly, and inhibited the increase of leaf relative conductivity, malondialdehyde (MDA) content, and lipoxygenase (LOX) activity effectively. Foliar spraying Spd also helped to the increase of leaf plasma membrane- and tonoplast H(+)-ATPase activity, but no significant difference was observed in the gene expression levels. These results suggested that exogenous Spd could significantly decrease the leaf lipid peroxidation and increase the proton pump activity, and thus, stabilize the leaf membrane structure and function, alleviate the damage induced by high temperature stress, and enhance the heat tolerance of cucumber seedlings.

[The effect of breviscapine on the pulmonary arterial pressure and the expression of Rho-kinase in pulmonary arterioles of hypoxic rats].

OBJECTIVE: To observe the effect of breviscapine on the pulmonary artery pressure and the Rho-kinase and Rho-kinase mRNA in pulmonary arterioles of rats treated with hypoxia, and therefore to explore the mechanisms of breviscapine on hypoxic pulmonary hypertension. METHODS: Eighteen adult male SD rats were randomly divided into 3 groups. One group was exposed to air (normal group), the second group was exposed to isobaric hypoxia for 3 weeks (hypoxic group), and the third group was exposed to hypoxia for 3 weeks and treated with breviscapine (preventive group). Cardiac catheterization was used to measure the mean pulmonary arterial pressure (mPAP). The heart was isolated, and the right ventricle (RV), left ventricle plus ventricular septum (LV + S) were weighed to calculate the ratio RV/(LV + S). The ratio of vascular wall thickness/vascular external diameter (WT%) and the ratio of vascular wall area/total vascular area (WA%) were measured by image analysis. The quantity of Rho-kinase and Rho-kinase mRNA in rat pulmonary arterioles were determined by immunohistochemistry and in situ hybridization respectively. RESULTS: The mPAP in the preventive group [(19.83 +/- 1.47) mm Hg, 1 mm Hg = 0.133 kPa] was significantly lower than that of the hypoxic group [(27.3 +/- 5.0) mm Hg], t = 4.28, P < 0.05. The RV/(LV + S) in the preventive group (0.29 +/- 0.03) was significantly lower than that in the hypoxic group (0.34 +/- 0.05, t = 2.39, P < 0.05). The WT% and WA% in the preventive group (25 +/- 5 and 45 +/- 5, respectively) were significantly lower than those in the hypoxic group (36 +/- 12 and 59 +/- 13, respectively, t = 4.89, 5.89, P < 0.05). The positive staining of ROCKI and ROCKII on pulmonary arterioles in the preventive group (1.18 +/- 0.10 and 1.30 +/- 0.12, respectively) were significantly lower than those in the hypoxic group (1.29 +/- 0.08 and 1.63 +/- 0.24, respectively, t = 3.90, 5.82, P < 0.05). The positive staining of ROCKI mRNA and ROCKII mRNA in the preventive group (1.23 +/- 0.13 and 1.22 +/- 0.06, respectively) were significantly lower than those in the hypoxic group (1.37 +/- 0.13 and 1.59 +/- 0.31, respectively, t = 3.94, 5.83, P < 0.05). CONCLUSION: Breviscapine was shown to prevent hypoxic pulmonary hypertension and decrease Rho-kinase and Rho-kinase mRNA.

[The role of bone morphogenetic protein-2 in the pathogenesis of hypoxic pulmonary hypertension].

OBJECTIVE: To investigate the change of bone morphogenetic protein-2 (BMP-2) in the lung tissues of rats with hypoxic pulmonary hypertension (HPH) and the role of BMP in the apoptosis of endothelial cells exposed to hypoxia. METHODS: Twenty male Wistar rats were randomly divided into two groups, the HPH group and the control group, 10 rats in each group. The HPH model was established by placing the rats in an isobaric chamber [O(2) = (10 +/- 0.5)%] for three weeks. The distribution of BMP-2 in pulmonary tissues was observed by using streptavidin peroxidase method (SP), and the morphologic changes of pulmonary arterioles and the integrated optical density (IA) of BMP-2 were determined by image analysis. The effect of Noggin (a blocking agent of BMP) on the apoptosis of hypoxic cultivated human umbilical vein endothelial cells (HUVEC) was assayed by flow cytometers. RESULTS: Compared to the control group, pulmonary artery hypertension was evident in the hypoxic rats: mPAP was 16.3 +/- 0.5 mm Hg (1 mm Hg = 0.133 kPa) vs (29.5 +/- 0.9) mm Hg, P < 0.01. In the hypoxic rats, the pulmonary arteriolar wall thickened significantly; WT% was (16 +/- 5)% vs (27 +/- 7)%, and WA% was (54 +/- 11)% vs (80 +/- 8)%, both P < 0.01. The distribution of BMP-2 was mainly in the pulmonary arteriolar walls. The IA of BMP-2 significantly increased (6124 +/- 1199 vs 13 463 +/- 5755, P < 0.01), and showed a positive linear relationship to WT% and WA% respectively (WT%: r = 0.744 P < 0.01; WA%: r = 0.693 P < 0.01). Hypoxia induced apoptosis of HUVEC; the apoptosis rate was increased from 6% to 14% and 25% after exposure to hypoxia for 24 h and 48 h respectively. The HUVEC apoptosis rate induced by hypoxia was reduced by Noggin to 11.91% (24 h) and 15.01% (48 h). CONCLUSIONS: Chronic hypoxia induced an increased expression of BMP-2, and a blocking agent of BMP inhibited the apoptosis of endothelial cells induced by hypoxia. It suggests that BMP may play an important role in the pathogenesis of hypoxic pulmonary hypertension.

[The clinical diagnosis value of fibro-optic bronchoscope examination combined with tumor marker determination to lung cancer].

OBJECTIVE: To investigate the diagnosis value of fibro-optic-bronchoscope combined with tumor maker determination to lung cancer. METHODS: By fibro-optic bronchoscope (FB) and electrochemiluminescence (ECL) examinations, 98 cases with lung cancer and 88 cases with benign lung disease were studied for calculating the detectable sensitivity and specificity to lung cancer, then further for evaluating the clinical value of FB examination combined with detection of tumor marker in serum/pleural fluid of patients with lung cancer. Results In patients with lung cancer, the serum levels of CEA, CA125 and CYFRA21-1 were (46.34 +/- 18.28) ng/mL, (83.34 +/- 33.26) U/mL and (25.67 +/- 10.32) ng/mL respectively, which were higher than those in patients with benign lung diseases. The serum levels of above three tumor markers in patients with lung cancer all were significantly higher than those in patients with benign lung diseases (P < 0.05). In the 36 specimens of pleural fluid, three tumor markers were higher than those in the corresponding serum samples. The detectable sensitivity of each tumor marker in pleural fluid was higher than that in serum. The sensitivity, specificity and overall accuracy of CEA in lung cancer were 37.5%, 87.5% and 63.6% respectively, of CA125 were 67.7%, 40.9% and 54.9%; of CYFRA21-1 were 56.3%, 81.8% and 68.5%; of FB were 60.4%, 100.0% and 79.4% respectively. The sensitivity, specificity or overall accuracy of fibro-optic bronchoscope combined with tumor marker (TM) examination to diagnosis of lung cancer was 90.6%, 92.0% or 91.3% respectively. CONCLUSION: The FB examination is valuable in diagnosing lung cancer, and by combined with TM determination, can further improve the accuracy to diagnosis of lung cancer.