The Effects Of Rapamycin On The Proliferation Of PASMC In Rats With Pulmonary Hypertension And Its Mechanism

Part ?: The establishment of a rat model of Pulmonary Arterial HypertensionObjective: To establish a rat model of pulmonary hypertension in rats, and to investigate the effect of high pulmonary blood flow on pulmonary artery pressure and pulmonary tissue structure.Method: There are thirty-two healthy male SD rats, were randomly divided into three groups: group I(control group, n = 8); II Group(sham operation group, right pulmonary artery sleeve but not ligation, external jugular vein and common carotid artery dissection doesn't anastomosis, n = 8); group III(pulmonary hypertension model group, the right pulmonary artery ligation and external carotid vein carotid artery anastomosis, n = 16). Application of Millar catheter and Powerlab system were measured in rat pulmonary artery pressure(Pap), and calculate right ventricular weight and left ventricle plus septum weight ratio(RV / LV + s), lung tissue sections stained by hematoxylin and eosin staining and elastic fiber staining, light microscope observation of lung tissue pathological changes.Result: Normal control group and sham operation group to the 12 weeks after hemodynamic detection, m PAP, respectively(14.35 0.85 + mm Hg and 16.32 + 1.53 mm Hg, P > 0.05) and RV / LV + s were(+ 0.20 0.01 0.21 0.01, P > 0.05). Pulmonary hypertension model group after 8 weeks, m PAP is 34.37 + 0.48 mm Hg, significantly higher than those in the normal control group and sham operation group(P < 0.01). After occlusion of the common carotid artery proximal, m PAP fell to 29.69 + 1.24 mm Hg, and clipping of anterior comparative(P < 0.01, but still higher than the normal control group and sham operation group(P < 0.01). Pulmonary hypertension model group after 12 weeks, m PAP was 3.5 + 2.20 mm Hg, significantly higher than those in the normal control group and sham operation group(P < 0.01), and postoperative 8 weeks, the difference no significant(P > 0.05), after occlusion of the common carotid artery proximal and pulmonary artery pressure by 3.5 + 2.20 mm Hg fell to 34.15 + 1.85 mm Hg(P > 0.05), significantly higher than that of normal control group and sham operation group(P < 0.01). Compared with control group and sham operation group, the RV/LV+S of pulmonary hypertension model group was significantly higher(8 weeks 0.55 + 0.05 vs 0.01 + 0.20 and 0.21 + 0.01, P< 0.01; 0.01 weeks 0.62 + 0.03 vs 0.01 + 0.20 and 0.21 + 12, P<0.01). Histological observation: the pulmonary artery hypertension model group of pulmonary artery smooth muscle cell proliferation is obvious, the wall thickness of the small artery increases, and the lumen stenosis, partial occlusion. 12 weeks later, the membrane muscle of the pulmonary artery was more obvious and the quantity increased, and even the non reversible changes of the new intima fibrosis and complete vascular occlusion.Conclusion: After 8 weeks ligation of right pulmonary artery and external jugular vein carotid artery anastomosis, there may be reversible changes in pulmonary vascular remodeling in rats, 12 weeks after the formation of a stable pulmonary hypertension model, pulmonary vascular remodeling significantly.Part ?: The effects of rapamycin on the proliferation of PASMC in rats with Pulmonary HypertensionObject: To establish a rat model of pulmonary hypertension in rats, to observe the effect of rapamycin on pulmonary hypertension, and to explore the mechanism of m TOR signaling pathway in the occurrence and development of pulmonary hypertension.Method: There are forty healthy male SD rats were randomly divided into 5 groups: group I: normal control group(n = 8); group II: pulmonary hypertension model group(right ligation of the pulmonary artery and external jugular vein and common carotid artery anastomosis, n = 8); group III: early intervention group(Rapa intervention from 1 to 4 weeks, n = 8). Group IV: full intervention group(Rapa intervention 1 ~ 12 weeks, n = 8); group V: late intervention group(Rapa intervention from 9 to 12 weeks, n = 8). Measurement of pulmonary artery pressure(PAP) in rats by Millar catheter and Powerlab system, and the ratio of right ventricular weight to left ventricular plus ventricular septal weight(RV/LV+S) was measured. Lung tissue sections after hematoxylin eosin staining, light microscope observation pulmonary morphologic changes, and calculate the pulmonary arterioles in film thickness for the percentage of vessel diameter(b) and pulmonary artery in the cross-sectional area of the film accounted for percentage of pulmonary vascular total cross-sectional area(MA%). The expression of-SMA and Ki67 in lung tissue was detected by immunofluorescence technique, and the expression of PS6 in lung tissue was detected by immunohistochemistry. The expression of PS6 and cyclin D1 in lung tissue was detected by Blot Western.Results: 1, pulmonary hypertension model group after 12 weeks, m PAP and RV / LV + s was significantly higher than that of control group(34.95 + 0.74 mm Hg vs which is 14.35 + 0.85 mm Hg, P < 0.001 and 0.61 + 0.03 vs 0.20 0.01, P < 0.01), MA% and MT% significantly increased(61.34 + 8.30 vs 30.93 + 5.59; 52.97 7.06 vs 15.15 + 3.29, P < 0.01), histological observation: small pulmonary artery tube wall thickness increased significantly, lumen area significantly smaller. Cyclin D1 and PS6 expression was significantly higher than the control group, the expression of ?-SMA, Ki67 was significantly higher than that of the control group. 2, Rapa early, full and late intervention, PAP and RV / LV + s respectively 28.79 + 1.46 mm Hg, 0.41 0.03; 22.59 + 0.84, 0.37 + 0.06 and 21.08 + 148 mm Hg, 0.33 + 0.06, compared with the model of pulmonary hypertension group were significantly reduce(P < 0.01). B and Ma% have varying degrees of decreases, respectively, for 46.99 + 585, 31.35 + 6.86; 46.37 + 4.02, 27.99 + 3.74 and 4.3 + 2.90, 25.59 + 3.37, and pulmonary artery hypertension model group(61.34 + 8.30, 52.97 + 706), P < 0.01. Histological observation showed that pulmonary small artery tube wall thickness has different degree decreases, the lumen area has increased to varying degrees, PS6, Cyclin D1 expression amount in different time have different levels of decline, a-SMA and Ki67 expression were compared with the model group declined and these improvements to Rapa whole and late intervention group was better than that of the early intervention group.Conclusion: Rapamycin inhibits the expression of m TOR pathway PS6, decreased cyclin D1 expression, inhibit the proliferation of pulmonary artery smooth muscle cells, thus in a certain extent, ease the occurrence and development of pulmonary arterial hypertension, suggesting that the m TOR pathway is expected to become the pulmonary high-pressure new preventive and therapeutic targets.