title: Mechanical mandible competence in rats with nutritional growth retardation.
abstract: OBJECTIVE
  In order to provide a better understanding of the sympathetic nervous system as a negative regulator of bone status, the aim of the study was to establish the biomechanical mandible response to different doses of a β-adrenergic antagonist such as propranolol (P) in a stress-induced food restriction model of growth retardation.
  
  
  METHODS
  Rats were assigned to eight groups: Control (C), C+P3.5 (CP3.5), C+P7 (CP7), C+P14 (CP14), NGR, NGR+P3.5 (NGRP3.5), NGR+P7 (NGRP7) and NGR+P14 (NGRP14). C, CP3.5, CP7 and CP14 rats were freely fed with the standard diet. NGR, NGRP3.5, NGRP7 and NGRP14 rats received, for 4 weeks (W4), 80% of the amount of controls food consumed. Propranolol 3.5, 7 and 14mg/kg/day was injected ip 5days per week in CP3.5 and NGRP3.5, CP7 and NGRP7, CP14 and NGRP14, respectively. At W4, zoometry, mandible morphometry, static histomorphometric and biomechanical competence were performed.
  
  
  RESULTS
  A dose of Propranolol 7mg/kg/day induced interradicular bone volume accretion reaching a mandible stiffness according to chronological age.
  
  
  CONCLUSIONS
  These findings evidenced that sympathetic nervous system activity is a negative regulator of mandible mechanical competence in the nutritional growth retardation model. Propranolol 7mg/kg/day, under the regimen usage, seems to be appropriate to blockade SNS activity on mandible mechanical performance in NGR rats, probably associated to an effect on bone mechanostat system ability to detect disuse mode as an error.
authors.affiliation: Department of Physiology, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Christian Esteban
authors.initials: CE
authors.lastname: Lezón
authors.affiliation: Department of Physiology, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Patricia Mabel
authors.initials: PM
authors.lastname: Pintos
authors.affiliation: Department of Physiology, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Clarisa
authors.initials: C
authors.lastname: Bozzini
authors.affiliation: Department of Physiology, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Alan Agüero
authors.initials: AA
authors.lastname: Romero
authors.affiliation: Department of General and Oral Biochemistry, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina; Department of Pediatrics, Nutrition Clinic, Clinical Hospital José de San Martin, School of Medicine, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Patricia
authors.initials: P
authors.lastname: Casavalle
authors.affiliation: Department of General and Oral Biochemistry, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina.
authors.forename: Silvia María
authors.initials: SM
authors.lastname: Friedman
authors.affiliation: Department of Physiology, School of Dentistry, University of Buenos Aires, Buenos Aires, Argentina. Electronic address: pboyer59@hotmail.com.
authors.forename: Patricia Mónica
authors.initials: PM
authors.lastname: Boyer
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D015415:Biomarkers; D001696:Biomechanical Phenomena; D001835:Body Weight; D001848:Bone Diseases, Developmental / Q000503:physiopathology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004548:Elasticity; D005508:Food Deprivation / Q000502:physiology*; D008297:Male; D008334:Mandible / Q000187:drug effects* / Q000254:growth & development* / Q000503:physiopathology; D009929:Organ Size / Q000187:drug effects; D011433:Propranolol / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D013564:Sympathetic Nervous System / Q000503:physiopathology*
chemical_list: D000319:Adrenergic beta-Antagonists; D015415:Biomarkers; D011433:Propranolol
keywords: Bone competence; Mandible; Nutritional growth retardation; Rat; β-Adrenergic blocker