The Effects And Mechanism Of TG2 Inhibitors On Pulmonary Vascular Remodeling In Rats With Pulmonary Arterial Hypertension

Objective:In this study,the rats with pulmonary arterial hypertension(PAH)were induced by left pneumonectomy plus monocrotaline(MCT)injection,to investigate the activation of transglutaminase 2(TG2)in the process of the formation of PAH and the relationship between TG2 and pulmonary vascular remodeling.And then to explore the intervention effects of cystamine dihydrochloride,one of TG2 inhibitor,on pulmonary arterial hypertension.This may provide a new target for the clinical treatment of PAH.Methods:1.Thirty healthy male Sprague-Dawley rats were randomly divided into 3 groups:control group(10 rats in each group):without any treatment,model group(10rats in each group):MCT(60 mg/kg;Sigma,USA)was injected subcutaneously1 week after left pneumonectomy.drug intervention group(10 rats in each group):Left pneumonectomy plus MCT injection same as the model group.cystamine dihydrochloride intervention at the 5th day after pneumonectomy,112mg/kg,qd,continuous dosing to postoperation 35 th.2.After finished the study,The rats were sacrificed after detecting the mean pulmonary arterial pressure in each group,calculate the right ventricle hypertrophy index.The methods of lung tissue HE staining,pulmonary elastic fiber dyeing were usedto observe the pulmonary blood vessels and the lung tissue pathology change,medial hypertrophy of small pulmonary arteries(WT%),vessel wall area to total area ratio(WA%)and lung small artery neointimal proliferation.3.The technology of RT-PCR was used to value the mRNA of TG2、5-HTT、ROCK2.4.The expression of TG2、5-HTT、ROCK2 were exhibited by western blot.Results:1.After 35 days,compared with the control group,the rats in the model group successfully established a model of PAH,mean pulmonary arterial pressure increased significantly.There has been a severe right ventricular hypertrophy,membrane thickening,and neointima increased significantly.Compared with the control group,the index of mPAP,right ventricular hypertrophy index,WT%,WA% and lung small artery neointimal proliferation were(55.60±5.75)mmHg、58.10±4.27%、46.03±7.14%、72.28±3.59%、78.77 ± 6.50%,which were significantly higher than those in control group[(22.02±1.98)mmHg、27.81±1.81%、21.66±4.23 %、31.95±4.04%、0,],The difference was statistically significant(P<0.01).2.After used cystamine dihydrochloride in intervention group,the indexes of mPAP,right ventricular hypertrophy,WT%,WA% and lung small artery neointimal proliferation were decreased compared with the model group,they were(36.19±2.67)mmHg、38.87±2.64%、25.61±6.62%、40.77±8.70%,22.18±4.52.The difference was statistically significant(P<0.01).3.Application of RT-PCR showed that the expression of model group rats TG2 of 5-HTT and Rock2 mRNA levels(3.06±0.53、2.35±0.40、7.80±1.82)were significantlyhigher than those in the control group(0.30±0.35、0.49±0.29、0.83±0.91),the difference was statistically significant(P<0.01);When given cystamine dihydrochloride intervention,compared with the model group intervention group of TG2,5-HTT and Rock2 mRNA expression levels were lower(1.28±1.35、1.15±0.93、1.61±1.17).The difference was statistically significant(P<0.01)4.Wsetern blot results showed that compared with the control group(1.35±0.12、1.54±0.12、0.57±0.05、0.92±0.11),the lung tissue TG2,5-HTT and RhoA and Rock2 expression of model group was significantly increased(2.18±0.16、2.17±0.09、1.12±0.07、1.64±0.08)(P<0.01),while the intervention group compared to model group,Reduced in different degrees(1.68±0.41、1.64±0.11、0.68±0.06、1.02±0.19.The difference was statistically significant(P<0.01).Conclusion : 1.The rats with pulmonary arterial hypertension were successfully induced by left pneumonectomy plus monocrotaline injection,With typical pathological features of pulmonary vascular remodeling of obstructive pulmonary hypertension.2.TG2 inhibitor,cystamine dihydrochloride,can attenuated the formation of PAH in certain degree.3.The intervention of cystamine dihydrochloride on Pulmonary vascular smooth muscle cell proliferation may be related to restrain activity of TG2,5-HT expression,and this process may be associated with the inhibition of activation RhoA/ROCK signaling pathway.4.RhoA/ROCK signaling pathway may be participate in the mechanism of Serotonin-induced pulmonary arterial hypertension...