title: [Adrenomedullin alleviates collagen accumulation in pulmonary arteries of rats with hypoxic pulmonary hypertension].
abstract: OBJECTIVE
  To observe the effect of adrenomedullin (ADM) on the pulmonary vascular collagen metabolism in hypoxic rats in order to study the effect of ADM on chronic hypoxic pulmonary vascular structural remodeling and its possible mechanism.
  
  
  METHODS
  Nineteen male Wistar rats were randomly divided into three groups: normal control (n=6), hypoxia (n=7) and ADM-treated hypoxia (n=6). ADM was subcutaneously administered into rats of the ADM-treated hypoxia group by mini-osmotic pump (300 ng/h) for two weeks. After two weeks of hypoxic challenge, mean pulmonary arterial pressure (mPAP) was evaluated using a right cardiac catheterization procedure. The ratio of right ventricular mass to left ventricular plus septal mass[RV/ (LV+S)] was measured. The changes of pulmonary vascular microstructure were observed. Meanwhile, the expression levels  of collagen I, collagen III and transforming growth factor (TGF)-β in pulmonary arteries were detected by immunohistochemical assay.
  
  
  RESULTS
  mPAP and RV/(LV+S) increased significantly in the hypoxia group compared with normal controls (P<0.01). The muscularization of small pulmonary vessels and the relative medial thickness of pulmonary arteries increased obviously in the hypoxia group compared with those in the normal control group (P<0.01). Meanwhile, the expression levels of collagen I, collagen III and TGF-β of pulmonary arteries in the hypoxia group increased markedly compared with those in the normal control group. However, mPAP and RV/(LV+S) were significantly reduced in the ADM-treated hypoxia group compared with those in the hypoxia group (P<0.01). ADM ameliorated pulmonary vascular structural remodeling of hypoxic rats, with a decrease in the expression of collagen I, collagen III and TGF-β of pulmonary arteries.
  
  
  CONCLUSIONS
  ADM might play a regulatory role in the development of hypoxic pulmonary hypertension and hypoxic pulmonary vascular remodeling, through inhibiting the expression of TGF-β and alleviating the collagen accumulation of pulmonary arteries.
authors.affiliation: Department of Pediatrics, Peking University First Hospital, Beijing 100034, China. qijianguang@sohu.com
authors.forename: Jian-Guang
authors.initials: JG
authors.lastname: Qi
authors.forename: Chang-Qing
authors.initials: CQ
authors.lastname: Xing
authors.forename: Ya-Guang
authors.initials: YG
authors.lastname: Ding
authors.forename: Jun-Bao
authors.initials: JB
authors.lastname: DU
mesh_terms: D053607:Adrenomedullin / Q000494:pharmacology*; D000818:Animals; D003094:Collagen / Q000378:metabolism*; D006976:Hypertension, Pulmonary / Q000209:etiology / Q000378:metabolism*; D000860:Hypoxia / Q000150:complications*; D008297:Male; D011651:Pulmonary Artery / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000502:physiology
chemical_list: D016212:Transforming Growth Factor beta; D053607:Adrenomedullin; D003094:Collagen