Fasudil Affected On Rabbits Pulmonary Hypertension Induced By Monocrotalin

Objective: Pulmonary hypertension (PH) is a life-threatening diseasecharacterized by the small pulmonary arteries vasospasm, endometrial cellproliferation and reconstruction of the vessel wall. Vasoconstriction, vascularwall remodeling, and thrombosis in situ formation are the three basic factorsof PH, the interaction of three factors could make the pulmonary vascularresistance was progressively increased, and would eventually lead to rightheart failure and death. Treatment of PH drugs primarily includes prostacyclinvegetarian class of endothelin receptor antagonists, phosphodiesteraseinhibitors and statin drugs at present, but because its pathogenesis is morecomplex, the effects of these traditional treatments are not very satisfactory, sothe development of new and effective treatment drugs of PH, has become a hottopic of research at home and abroad. Fasudil (hexahydrophthalic-1-(5-sulfonyl isoquinoline)-1(H)-1,4-diaza), as a representative of the Rhokinase inhibitor, which is a new type of isoquinoline sulfonamide derivatives,reduce pulmonary artery pressure by inhibition of Rho kinase, inhibition ofvasoconstriction, inhibition hyperlasia of vascular smooth muscle cells,antagonism dysfunction of endothelial cell, inhibition of vessel wallreconstruction and other mechanisms. In this study, on the basis of therabbits PH model induced by monocrotaline, the choice of fasudil interventedPH model, and observed that Fasudil could reduce PH rabbit pulmonaryartery pressure or not, and further texplored its mechanism, to provide a lawtheoretical basis of the fasudil for the clinical application of PH patients.Methods:18healthy New Zealand rabbits were randomized into threegroups:①The control group (control group, n=6),②The PH model group(model group, n=6) and③The PH+Fasudil group (treatment group, n=6). Under the same feed and rearing conditions, the model group and treatment group given a one-time monocrotaline solution (1:5mixing dissolved withethanol and saline) and by intraperitoneal bolus injection and60mg/kginjected into the abdominal cavity of rabbits. The control group, in the sameway one-time injected the same dose of ethanol and saline mixture into theabdominal cavity. After feeding for4weeks, then drug intervented. Treatmentgroup by intraperitoneally injected fasudil by15ml/kg/d (fasudil in press2ml/kg diluted into normal saline), while the control group and model groupwere injected intraperitoneally with normal saline by15ml/kg/d for4weeks.After the end of the experiment, rabbits were anesthetized to determinatemean pulmonary artery pressure (mPAP)of groups by right heartcatheterization method, after the end of the pressure measurement,immediately opened thoracic cavity and removed the heart, separated theright ventricle (RV) and left ventricle plus interventricular septum (LV+IVS),and in turn weighed to calculate the ratio of RV/(LV+IVS)[right ventricularhypertrophy index (RVHI)] in order to determine whether right ventricularhypertrophy or not and the degree of hypertrophy. And immediately removedthe lung tissue, placed in formaldehyde solution, fixed72hours, embeddedin paraffin, then sliced, HE stained and observed under light microscope andphotographed. In addition, at the beginning of the experiment and2,4,6,8weeks, bleed got from the rabbit ear vein blood and plasma NO and ET-1values were measured using nitrate reductase method and radioimmunoassay.Results:1Observation of general situations of rabbitsModel and treated groups of rabbits after intraperitoneal injection ofmonocrotaline, rabbits began to appear dull coat, shortness of breath, reducedfood intake, body weight compared with the control group increased slowly onthe seventh day, while the control group of rabbits was easily coat shiny andsmooth breathing and moved easily. Treatment group after4weeks of FasudilThereafter, rabbit shortness of breath symptoms gradually improved, wasslightly shiny coat, food intaked and weight gained more than the previous.2Comparison of the mean pulmonary artery pressure (mPAP) For the Control group, model group and treatment group, the levels of themean pulmonary artery pressure were (15.15±1.35) mmHg,(40.48±1.75)mmHg,(27.26±2.26) mmHg. When compared with the control group, themean pulmonary artery pressure of the model group and treatment group wassignificantly increased (P <0.05); the increased extent of the mean pulmonaryartery pressure in treatment group was less than model group (P <0.05).3Comparison of the right ventricular hypertrophy index (RVHI):The levels of the control group, model group, treatment group RVHI wereas follows:(0.36±0.13)(0.29±0.09)(0.27±0.06), compared with thecontrol group, the right ventricular hypertrophy indexes of model group andtreatment group, were significantly increased (P <0.01); the increased extentof RVHI in treatment group was less than model group (P <0.05).4Pathological changes of the lung tissue:Compared with the control group, the small pulmonary artery walls ofmodel group and treatment group after the injection of monocrotaline in NewZealand rabbits thickened, vascular smooth muscle tissue and elastic fiberlayer was significantly hyperplasia, the lumen decreases, endometrial cellswas uneven proliferation; compared with model group, vessel wall thickeningand luminal narrowing were weakened, reduced the infiltration ofinflammatory cells, The proliferation of the elastic fiber layer and the machinephenomenons of non-muscular arteries had improved.5Comparison of NO levelsCompared with the control group, the plasma NO levels of model group andtreatment group were significantly decreased(P <0.05),on4and8weeks; On8weeks,compared with model, the plasma NO levels of treatment group weresignificantly increased (P <0.05).6Comparison of ET-1levelsCompared with the control group, the plasma ET-1levels of model group andtreatment group were significantly increased(P <0.05),on4and8weeks; On8weeks,compared with model, the plasma ET-1levels of treatment group weresignificantly decreased (P <0.05). Conclusion:1The mPAP levels of model group and treatment group weresignificantly higher than the control group, while the mPAP levels of thetreatment group was lower than the model group (all P <0.05), the studysuggested that PH could be induced by monocrotaline, while fasudil couldreduce pulmonary artery pressure to a certain extent, and inhibited theformation and progression of the right ventricular hypertrophy.2The RVHI of model group and treatment group was significantly higherthan the control group, while the RVHI of the treatment group was lower thanthe model group (all P <0.05), the study suggested that right ventricularhypertrophy could be induced by monocrotaline, while fasudil could inhibitedthe formation and progression of the right ventricular hypertrophy to a certainextent.3Compared with the control group, we would know that pulmonaryartery wall thickened, luminal narrowed, accompanied by inflammatory cellinfiltration, hyperplasia of elastic fibers, the non-muscular arterioles organizedin model group and treatment group. the changes of the treatment group wereweaker than the model group. The study suggested that monocrotaline couldmake the New Zealand rabbit pulmonary artery reconstruction, fasudilinhibited and reversed pulmonary vascular remodeling process in a certaindegree to reduce pulmonary artery pressure.4Compared with the control group, the NO levels of model group groupand treatment group was lower(P<0.05), the ET-1levels of model group werehigher; compared with the model group, the NO levels increased and the ET-1levels decreased(p<0.05).The study suggested that fasudil could reduce ET-1level and improve NO level, improved endothelial function and inhibitedpulmonary vascular contraction to reduced pulmonary artery pressure.