title: Effect of thoracic epidural blockade on hypoxia-induced pulmonary arterial hypertension in rats.
abstract: OBJECTIVE
  The present study was aimed to investigate the influence of thoracic epidural blockade on hypoxia-induced pulmonary hypertension in rats.
  
  
  METHODS
  Forty eight Wistar rats were randomly divided into 4 equal groups, named normoxia hypoxia hypoxia/ ropivacaine and hypoxia/saline. Animals were placed in a hypoxia chamber and instrumented with epidural catheters at the thoracic level. Rats were injected with saline or ropivacaine. Haemodynamic measurements included pulmonary artery pressure and right ventricular hypertrophy. Degree of pulmonary vascular remodeling was determined by Hematoxylin and Eosin (HE) staining. Serum cyclic GMP (cGMP) and TNF-α were measured using radioimmuno assay. Real-time PCR and western boltting were employed to examine the expression of cAMP responding-element binding protein (CREB).
  
  
  RESULTS
  We found that the thoracic epidural blockade significantly decreased chronic hypoxia-induced pulmonary hypertension and vascular remodeling in rats. Ropivacaine-treated rats exhibited significantly lower mean pulmonary artery pressure (mPAP), ratio of right ventricular weight to left ventricular plus septal weight (RV/(LV+S)) and wall thickness of pulmonary artery compared with those of control rats. Hypoxia-induced increase in levels of serum cGMP and TNF-α was reversed by thoracic epidural blockade. Moreover, hypoxia increased expression of CREB at mRNA and protein levels which could be suppressed by thoracic epidural blockade.
  
  
  CONCLUSIONS
  Thoracic epidural blockade reduced mPAP and serum level of TNF-α and increased cGMP. The treatment reversed upregulated expression of CREB at mRNA and protein production.
authors.affiliation: Institute of Pulmonary Disease, the First Hospital of China Medical University, Shenyang, China, 110001 ; First Hospital of Harbin Medical University, Harbin, China, 150001.
authors.forename: Shi-Huan
authors.initials: SH
authors.lastname: Yu
authors.affiliation: First Hospital of Harbin Medical University, Harbin, China, 150001.
authors.forename: Jing-Ying
authors.initials: JY
authors.lastname: Chen
authors.affiliation: First Hospital of Harbin Medical University, Harbin, China, 150001.
authors.forename: Yi-Mei
authors.initials: YM
authors.lastname: Zhang
authors.affiliation: First Hospital of Harbin Medical University, Harbin, China, 150001.
authors.forename: Gui-Wei
authors.initials: GW
authors.lastname: Jiao
authors.affiliation: First Hospital of Harbin Medical University, Harbin, China, 150001.
authors.forename: Feng-Qi
authors.initials: FQ
authors.lastname: Liu
authors.affiliation: First Hospital of Harbin Medical University, Harbin, China, 150001.
authors.forename: Ling-Fei
authors.initials: LF
authors.lastname: Kong
keywords: CREB; Hypoxia; Pulmonary arterial hypertension; Thoracic epidural blockade TNF-α