Atorvastatin Attenuates Dehydromonocrotaline-induced Pulmonary Hypertension In Beagles At Early Stage

Part I:Establishment of Pulmonary Hypertension Induced by Dehydromonocrotaline of Beagles[Objective] To explore the establishment of pulmonary hypertension model induced by dehydromonocrotaline and use the Vigilance monitor system with principles of continuous thermodilution method to measure cardiac output (CO).[Methods] The beagles were randomly divided into two groups, the experimental group (2mg/kg dehydromonocrotaline, n=5) and the control group (lml/kg dimethylformamide, n=5). The drugs were administered to beagles via a right atrium injection in the experimental group. The acceleration time (ACT), the right ventricular ejection before the time (RPEP), the Tei index were measured by the echocardiography and the pulmonary arterial mean pressure (PAMP), the pulmonary wedge pressure(PCWP) were measured by the Swan-Ganz Catheter and the CO was determined by the Vigilance monitor system using the continuous thermodilution method at baseline and eight weeks after the drug administration.We can obtain the PVR according to the formula(PVR= 80X (mPAP-PCWP)/CO)at the same time from this system. At last, pathological autopsy and hematoxylin-eosin staining were performed after the beagles died.[Results]1?After 8 weeks of injection,compared with the control group, the experimental group lost of appetite, reduced activity, the reaction down and shortness of breath.2?The Tei index of the experimental group increased significantly compared with this of the control group (P<0.05) 8 weeks after injection. The ACT and the TAPSE of the experimental group significantly reduced compared with those of the control group (P<0.05).3?In the experimental group, the PAMP was increased (16.00±2.74mmHg vs 32.00±11.40, P<0.001),and the CO was decreased (4.64±0.50 L/min vs 1.56±0.32L/min, P=0.035) 8 weeks after injection of DHMC, while the PAMP and CO remained unchanged in the control group.4?The medial of pulmonary artery wall and external elastic membrane proliferated were observed in the experimental group. [Conclusion] The beagle model of pulmonary hypertension induced by dehydromonocrotaline was successfully. The technology using the Vigilance monitor system with principles of continuous thermodilution method was simple, convenient and repeatable and thus can be widely applied.Part?:Atorvastatin Effects on Pulmonary Vascular of Dehydromonocrotaline-Induced Pulmonary Hypertension Beagles[Objective] To assess whether atorvastatin is capable of attenuating pulmonary hypertension induced by DHMC in beagles and explore potential mechanisms of statin on the pulmonary vascular.[Methods] DHMC was artificially synthesized as described by Mattocks and confirmed its structure and concentration using high performance liquid chromatography (HPLC). Our research was on eighteen 3-month-old beagles weighted 10?15kg, no sex limitation. We used the continuous thermodilution method of hemodynamic measurements and arterial blood gases measured at baseline. Beagles were injected DHMC in on Day 1 and divided into three groups: the atorvastatin group(DHMC +2mg/kg atorvatatin, n=7), the monocrotaline group (DHMC +vehicle, n=5), and the normal group (lml/kg dimethylformamide, n=5). 8 weeks later, the beagles were given a hemodynamic evaluation with the continuous thermodilution method followed by cardiac and pulmonary tissue sampling for morphometry, immunohistochemistry, and real-time quantitative PCR.[Results]1?8 weeks after injection, the RPEP?RPEP/ACT?the Tei index of the monocrotaline group increased significantly compared with those of the atorvastatin group (P<0.05). The ACT and the TAPSE of the monocrotaline group significantly reduced compared with those of the atorvastatin and normal group (P<0.05).2?The atorvastatin-treated beagles demonstrated lower PAMP than the monocrotaline group(14.71±3.25mmHg vs 32.00±11.40mmHg, P<0.05) at 8 weeks. 3?Less pulmonary endothelium reconstruction and smooth muscle cell proliferation were demonstrated in the atorvastatin-treated beagles. The Caspase-3 was positive in the atorvastatin group compared with this of the monocrotaline group(35.22±8.38 vs 8.19±4.91, P<0.05). The monocrotaline group were positive for a-SMA expression, but only a small amount of expression of pulmonary artery in the atorvastatin-treated group (15.74±2.38 vs 38.63±10.1,P<0.05).4?Pulmonary preproET-1 RNA expressions were increased in monocrotaline beagles but decreased toward normal levels in atorvastatin-treated group. eNOS mRNA was decreased in the monocrotaline beagles but increased in the atorvastatin-treated group.[Conclusions] Atorvastatin attenuates DHMC-induced pulmonary hypertension in beagles through inhibition of HMG-CoA reductase. Atorvastatin drugs inhibition of vasoactive substances and reversal of pulmonary vascular remodeling induced smooth muscle cell apoptosis may be an important mechanism of statin effect.Part?:Atorvastatin Attenuates the Development of Monocrotaline-Induced Pulmonary Hypertension through Reduction of Inflammation[Objective] To determine the possible prevention of atorvastatin on pulmonary hypertension, we investigated the protective effects of atorvastatin on dehydromonocrotaline (DHMC) induced pulmonary hypertension in beagles through reduction of anti-inflammation.[Methods] DHMC was artificially synthesized as described by Mattocks. The beagles, aged 10 month, weighting 10?15kg, no sex limitation, were randomly divided into three groups:the atorvastatin group(2mg/kg atorvatatin+DHMC, n=7), the monocrotaline group (vehicle+DHMC, n=5), and the normal group (lml/kg dimethylformamide, n=5). Each group of lung tissue section of the pulmonary arterial wall area/area ratio (W/V) and the wall thickness/outer diameter ratio (WT/D) were analyzed by the application pathological image analysis system. The lung tissue of IL-1?, TNF-?and VEGF mRNA expression were detected with real-time quantitative PCR method.[Results]1?W/V and WT/D was significantly higher in monocrotaline group than the atorvastatin group (10.41±0.47% vs 6.641±0.48%,31.67±0.39% vs 16.97±0.62%). The pulmonary arterial inflammation score was significantly higher in the monocrotaline group than that of atorvastatin group (P<0.05).2?The transcription level of IL-1?, TNF-?and VEGF mRNA in the atorvastatin group was significantly lower than the monocrotaline group (P<0.05).[Conclusions]1?Atorvastatin can reduce pulmonary vascular lesions of pulmonary hypertension in dogs around the infiltration of inflammatory cells.2?Atorvastatin drug can inhibit the pulmonary artery wall thickening.3?Atorvastatin can inhibits IL-1?, TNF-?and VEGF mRNA expression and reduce inflammation of the pulmonary artery injury.