title: Beta-adrenoceptor blockade delays granulation tissue formation in polyurethane sponge implants.
abstract: BACKGROUND
  The role of adrenoceptors in granulation tissue formation is not well understood. The aim of this study was to investigate the effects of alpha- and beta-adrenoceptor blockade on granulation tissue development using polyurethane (PU) implants in the rat.
  
  
  METHODS
  Animals were treated orally with propranolol (beta1- and beta2-antagonist), atenolol (beta1-antagonist) or phentolamine (alpha1- and alpha2-antagonist) until euthanasia. The control group received only water. All animals received subcutaneous implants of PU sponges. After 14 days, implants were collected, formalin-fixed and paraffin-embedded. Sections were stained with hematoxylin and eosin and Sirius red and immunostained for CD68 and alpha-smooth muscle actin.
  
  
  RESULTS
  The number of inflammatory cells and the volume density of myofibroblasts and blood vessels were lower in the control group than in the propranolol- and atenolol-treated groups. The collagen fiber score was greater in the control group than in the propranolol- and atenolol-treated groups. The inflammatory infiltrate, collagen fiber score, blood vessel density or myofibroblast differentiation was not affected by phentolamine. The percentage of fibrovascular invasion was greater in the antagonist-treated groups than in the control group.
  
  
  CONCLUSIONS
  Blockade of beta1- and beta2-adrenoceptors, but not alpha-adrenoceptors, impairs granulation tissue development in PU implants due to interference with the inflammatory response.
authors.affiliation: Department of Histology and Embryology, State University of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Bruna
authors.initials: B
authors.lastname: Romana-Souza
authors.forename: Jeanine S
authors.initials: JS
authors.lastname: Santos
authors.forename: Alexis
authors.initials: A
authors.lastname: Desmoulière
authors.forename: Andréa
authors.initials: A
authors.lastname: Monte-Alto-Costa
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D003094:Collagen / Q000187:drug effects; D006097:Granulation Tissue / Q000187:drug effects* / Q000473:pathology*; D007150:Immunohistochemistry; D020007:Implants, Experimental / Q000009:adverse effects; D008297:Male; D011140:Polyurethanes / Q000009:adverse effects; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D011943:Receptors, Adrenergic, beta / Q000187:drug effects
chemical_list: D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D011140:Polyurethanes; D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D003094:Collagen