Investigate The Mechanism Of Inflammation &Apoptosis That Carrageenin Transduced In The Rat Model Of Chronic Thromboembolic Pulmonary Hypertension

Objective:Combined the clots with carrageenin to generate an reliable rat model of chronic thromboembolic pulmonary hypertension which resembles the functional and histological features of CTEPH patients;and to disclose the potent role of inflammation and apoptosis that may played in the pathogenesis of chronic thromboembolic pulmonary hypertension.Method:Male adult Sprague Dawley rats were randomly divided into three groups: control group,group A,group B.Autologous blood clots were made one night before,and then inject 32±5 clots with 1 mm in diameter and 3mm to the pulmonary arteries through left jugular vein,after doing that the experimental group were peritoneal injection of 10% tranexamic acid(200mg/kg)per day,and the group B was given another more peritoneal injection of 0.2%carrageenin(20mg/kg)per week,while the control group was doing the same operation,beside the saline was instead of tranexamic acid.Repeat the operate in the fourth and eleventh day after the first and second embolization,then check in the third week after the last operate.Investigate the pathological changes of lung tissues by HE.The pathologic changes in the the vessel walls was assessed by immunohistochemistry.RT-PCR and western-blot was done to determined the mRNA and protein expression of NF-a,BCL-2,NF-KB/p65 and BAX.Result: Vascular remodeling was found in the chronic pulmonary embolism rats.The Pulmonary arterial pressure in the group A was much higher compare with the control group(25.51±1.13 vs 15.92±1.13,p<0.05);statistically different was found in the group B compare with group A(29.82±1.26vs25.51±1.13,p<0.05),andclots were still found in the Largemedium sized pulmonary artery in the group B,3 weeks later after the third operation.Hematoxylin and eosin pathology suggest that pulmonary artery wall in the control group is normal,no artery intimal hyperplasia was found nor the narrowing;whilepulmonary artery wall in the group A was thickening with inhomogeneous,which narrowing the vessels.The narrowing and thickening demonstrate much more sever in the group B,endothelial proliferation was significantlyassessed by Immunohistochemistry with VIII,and we can even found clots embolism in the pulmonary artery.According to the vascular remodeling analysis by WA/TA,The Pulmonary arterial wall in the group A was much thicker than the control group(76.41±5.97 vs 35.39±7.30 p<0.05);statistically different also exist in the group B compare with group A(85.41±7.37 vs 76.41±5.97 p<0.05)).The expression of TNF-a,BCL-2 and NF-KB/p65 were upregulated steadily in a time-dependent manner,further the expression of the described also increased with multiple embolism,while BAX do the controversy.Conclusion: carrageenin combined with clots can help to establish an reliable rat model of chronic thromboembolic pulmonary,which can resemble the functional and histological features of CTEPH patients.The upregulated expression of TNF-?,BCL-2 a,NF-KB/p65 and the down-regulated of BAX cause an significantly endothelial proliferation,suggest that inflammation may suppress the apoptosis and play an important role in the pathogenesis of chronic thromboembolic which may open a new door to explore the therapy of CTEPH.