title: Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression.
abstract: The mandible condylar process cartilage (CP) of Wistar rats is a secondary cartilage and acts as a mandibular growth site. This phenomenon depends on adequate proteins intake and hormone actions, including insulin.
  
  
  OBJECTIVE
  The present study evaluated the morphological aspects and the expression of the insulin receptor (IR) in the cartilage of the condylar process (CP) of rats subjected to protein undernourishment.
  
  
  METHODS
  The nourished group received a 20% casein diet, while the undernourished group (U) received a 5% casein diet. The re-nourished groups, R and RR, were used to assess the effects of re-nutrition during puberty and adulthood, respectively. CPs were processed and stained with picro-sirius red, safranin-O and azocarmine. Scanning electron microscopy and immunohistochemistry were also performed.
  
  
  RESULTS
  The area of the CP cartilage and the number of cells in the chondroblastic layer decreased in the U group, as did the thickness of the CP layer in the joint and hypertrophic layer. Renourishment during the pubertal stage, but not during the adult phase, restored these parameters. The cell number was restored when re-nutrition occurred in the pubertal stage, but not in the adult phase. The extracellular matrix also decreased in the U group, but was restored by re-nutrition during the pubertal stage and further increased in the adult phase. IR expression was observed in all CPs, being higher in the chondroblastic and hypertrophic cartilage layers. The lowest expression was found in the U and RR groups.
  
  
  CONCLUSIONS
  Protein malnutrition altered the cellularity, the area, and the fibrous cartilage complex, as well as the expression of the IRs.
authors.affiliation: Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Marcelo Arthur
authors.initials: MA
authors.lastname: Cavalli
authors.affiliation: Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Aline
authors.initials: A
authors.lastname: Gonçalves
authors.affiliation: Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Joice Naiara Bertaglia
authors.initials: JN
authors.lastname: Pereira
authors.affiliation: Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Jodonai Barbosa da
authors.initials: JB
authors.lastname: Silva
authors.affiliation: Department of Anatomy, Biomedical Science Institute, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Silvia de Campos
authors.initials: Sde C
authors.lastname: Boldrini
authors.affiliation: Department of Anatomy, Biomedical Science Institute, University of São Paulo, São Paulo, SP, Brazil.
authors.forename: Edson Aparecido
authors.initials: EA
authors.lastname: Liberti
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000378:metabolism*; D002452:Cell Count; D019902:Chondrocytes / Q000502:physiology; D003094:Collagen / Q000032:analysis; D005260:Female; D007150:Immunohistochemistry; D008297:Male; D008335:Mandibular Condyle / Q000166:cytology / Q000378:metabolism*; D008855:Microscopy, Electron, Scanning; D011488:Protein Deficiency / Q000378:metabolism*; D017208:Rats, Wistar; D011972:Receptor, Insulin / Q000032:analysis / Q000378:metabolism*; D013997:Time Factors
chemical_list: D003094:Collagen; D011972:Receptor, Insulin