The Role And Mechanism Of Relm-β Regulated Signal Pathway PLC/IP₃ On Pulmonary Vascular Remodeling In Rats With Monocrotaline Induced Pulmonary Hypertension

Objective:Establishing the rat model of Monccrotalire-induced pulmonary hypertension,to observe the effect of RELM-βon pulmonary vascular remodeling and pulmonary hypertension in this model,and whether those role of RELM-βwas played by regulating PLC/IP₃ signaling pathway after intervention of RELM-βexpression.Methods:The experiment is divided into two parts:（1）PART I:The Groups of Experiments:saline control group（blank control group）,monocrotaline group,no-load lentivirus saline group （negative control:no-load saline group）,no-load lentivirus monocrotaline group（negative control:no-load MCT group）,Silent Lentivirus expression RELM-βsaline group（Silent saline group）,Silent Lentivirus expression RELM-βmonocrotaline group（Silent MCT group）,overexpress Lentivirus RELM-βsaline group（overexpress saline group）,overexpress Lentivirus RELM-βmonocrotaline group（overexpress MCT group）.The model of monocrotaline induced pulmonary hypertension（MCT-PH）was established by intraperitoneal injection of monocrotaline（50mg/KG）.The mean pulmonary arterial pressure（mPAP）and Fulton index of the rats were measured by right cardiac catheterization and weighing method,and the morphological changes of pulmonary vessels were observed by HE staining.The expression of RELM-β,PLC and IP₃R in lung tissue was detected by immunohistochemistry,Western blot and real-time PCR.（2）PART II:Lentiviruses with silent expression and overexpression of RELM-βgene were transfected into the lungs after tracheotomy,The dosage of silent and over expressed lentivirus was 1.5×108 Tu/animal,and the solute of negative control group was no load lentivirus.and the effects of the intervention of RELM-βexpression on the mPAP,Fulton index and vascular morphology were measured respectively.Immunohistochemistry,WB and PCR other methods were used to detect the expression of RELM-β,PLC and IP₃R in lung tissues after interference with RELM-βexpression.Results:（1）PART I:The mean pulmonary artery pressure and right ventricular index in MCT group rats were significantly increased（P<0.05）,and the lumen was narrowed and the wall was significantly thickened.The expression of RELM-β,PLC,IP₃R protein and mRNA in lung tissue of MCT group were increased by immunohistochemistry,WB and PCR methods（P<0.05）.（2）PART II:After the intervention of RELM-β,expression,the hemodynamic indexes of Silent MCT group were significantly decreased（P<0.05）,and the degree of arterial lumen stenosis and wall thickening were significantly improved.The hemodynamic indexes of the overexpress saline group were increased（P<0.05）,the lumen stenosis,wall thickening and pulmonary vascular remodeling were observed under light microscope.But the hemodynamic indexes of the overexpression MCT group showed no statistical significance compared with no load MCT group（P>0.05）.The expression of RELM-β,PLC and IP₃R in the lung tissues of rats were decreased after transfection with silent expression lentivirus of RELM-β（P<0.05）,and were increased after transfection with overexpression lentivirus of RELM-β（P<0.05）。It was suggested that intervention of RELM-βcan affect the expression levels of PLC and IP₃R in pulmonary artery.Conclusions:1、MCT can induce pulmonary vascular remodeling and pulmonary hypertension.It was also found that MCT can promote the expression of RELM-β,PLC and IP₃ in the lung tissue.2、The intervention of RELM-βexpression in the lungs of rats can affect the pulmonary vascular remodeling and the formation of pulmonary hypertension,and may play a role through the PLC/IP₃pathway.