The Role Of Macrophage Migration Inhibitory Factor In Rabbit Model Of Systemic Sclerosis Associated Pulmonary Arterial Hypertension

Objective:To explore the role of MIF in rabbit model of SSc-PAH induced by monocrotaline combined with bleomycin.Methods:Part?:50 male rabbits were randomly divided into five groups: control group A,group B: Large dose MCT group,group C: Small dose MCT group,Group D(BLM combined with MCT),group E: adequate BLM group.Group B and C were injected monocrotaline by intraperitoneal,Dosages of MCT were 60 mg.kg-1 and 40 mg.kg-1,respectively,Group D and E were given by BLM(100 ul)peritoneal injection once a day.Group D were injected monocrotaline(Dosages of MCT were 40 mg.kg-1)by intraperitoneal,And the control group was administered with equal dose of solvent by intraperitoneal injection.Observe the animal's food,exercise,skin change and weigh once a week.After 3 weeks,the pulmonary artery pressure and the right ventricular hypertrophy index was measured,and the pathological changes were observed in skin,pulmonary artery stem,lung tissue.Part?:30 male rabbits were randomly divided into three groups: normal control group(n=10),model group(n=10),MIF targeted therapy group(n=10).Model group and MIF targeted therapy group were managed in the same way as described above to establish the SSc-PAH model,while MIF targeted group were injected ISO-1 0.66 mg/(kg·d)by intraperitoneal,normal control group were given the same volume of sham solution.After 3 weeks,RVHI were measured,H&E staining were conducted,western blotting were used to detect the expression of MIF in pulmonary tissues.Results:Part?:1 General situation: 10 days after the injection of drugs,the hair of rabbits in group B,C,D were lustrous,the respiration rates were increased,the activity tolerance decreased and the appetite decreased.From the 16 th day,the group D and E showedlocal thickening of the skin hardens,poor elasticity,no hair growth in the abdominal region.The group A did not show the above changes,the fur was bright,the activity was good,the water intake was good,and the weight increased over time.There were2 deaths in the BLM and MCT groups,and the rate of successfully establish an SSc-PAH animal model was 80%.2 In group B,C,D,RVHI and mPAP were increased,the differences were statistically significant when compared with normal control group and Group E.3 The histopathological examination of Group D and E revealed dermal sclerosis characterized by epidermal thickness,thickened collagen bundles and deposition of homogenous materials in the thickened dermis,hair follicles and skin appendages were diminished or even disappear,group A,B and C did not appear the above changes.Compared with group A and E,the pulmonary arterioles in group B,C and D were significantly thickened,the lumen stenosis,and occlusion of pulmonary arteries,inflammatory cells infiltration,effused red cells in alveolus were observed in the lung tissues.While the pathologic changes were not observed in normal control group.Part?:1 RVHI and mPAP were increased in model group when compared with normal control group,while the targeted therapy group has the same result.2 Histopathological examination showed epidermal and dermis thickness,dermis fibrosis,skin appendages diminished,increase in wall thickness and occlusion of pulmonary arteries and inflammatory cells infiltration.3 Western blotting indicated that the expression of MIF in pulmonary tissues in model group and the targeted therapy group were higher than normal control group(P< 0.05);the expression of MIF in the targeted therapy group were lower than model control group,while had significant difference from model control group.4 Immunohistochemistry showed that MIF were highly expressed in the lung tissues of the model group and located in the intima and media of the pulmonary arterioles.The MIF-targeting inhibition group showed low expression of MIF.Conclusion:1.Monocrotaline(40 mg/kg)combine bleomycin intraperitoneal injection can successfully simulate the model of SSc-PAH.Compared with the large dose of MCT(60 mg/kg),low dose of MCT(40 mg/kg)reducing its mortality and increasing the success rate.2.The expression of MIF in pulmonary tissues were higher in SSc-PAH model,while reduction of symptoms and pathology after targeting inhibition.It's indicating MIF might play a pivotal role in rabbit model of SSc-PAH.