title: Analysis of synovial fluid of the Capybara's stifle joints.
abstract: BACKGROUND
  Although normal synovial fluid has been well characterized in domestic animals such as dogs, cats, horses, and cows, the available information on larger rodents is scarce.
  
  
  OBJECTIVE
  The purpose of the study was to analyze the physical, chemical, and cytologic characteristics of the synovial fluid in stifle joints of Capybaras.
  
  
  METHODS
  Five free-ranging adult female Capybaras (Hydrochoerus hydrochaeris), weighing from 37 to 56 kg were used. Synovial fluid was obtained by aspiration of 10 stifle joints. Samples were analyzed for physical, chemical, and cytologic properties.
  
  
  RESULTS
  Spontaneous clotting was negative in 9 samples. Most synovial fluids had pH 8, and protein concentrations ranged from 1.6 to 3.6 g/dL. The mucin clot test was good in all 6 samples that were tested. Nucleated cell counts ranged from 140 to 508 cells/μL. Relative differential leukocyte counts demonstrated a predominance of mononuclear cells (97.6%), including 76.2% undifferentiated mononuclear cells, 18.1% macrophages, and 3.66% lymphocytes. Polymorphonuclear cells included 1.83% neutrophils and 0.2% eosinophils.
  
  
  CONCLUSIONS
  The synovial stifle joint fluid of healthy free-ranging adult Capybaras is clear, colorless, viscous, and with chemical features and cytologic findings similar to those seen in domestic animals.
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista (UNESP), Botucatu, Brazil.
authors.forename: Giovanna C
authors.initials: GC
authors.lastname: Brombini
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista (UNESP), Botucatu, Brazil.
authors.forename: Sheila C
authors.initials: SC
authors.lastname: Rahal
authors.affiliation: Department of Veterinary Clinic, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista (UNESP), Botucatu, Brazil.
authors.forename: Bruno C S
authors.initials: BC
authors.lastname: Bergamini
authors.affiliation: Department of Veterinary Clinic, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista (UNESP), Botucatu, Brazil.
authors.forename: Raimundo S
authors.initials: RS
authors.lastname: Lopes
authors.affiliation: Department of Veterinary Surgery and Anesthesiology, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista (UNESP), Botucatu, Brazil.
authors.forename: Ivan F C
authors.initials: IF
authors.lastname: Santos
authors.affiliation: Department of Anatomy, Institute of Biosciences, Universidade Estadual Paulista (UNESP), Botucatu, Brazil.
authors.forename: Bruno C
authors.initials: BC
authors.lastname: Schimming
mesh_terms: D000818:Animals; D005260:Female; D007596:Joints / Q000166:cytology; D007958:Leukocyte Count / Q000662:veterinary; D008264:Macrophages / Q000166:cytology; D009504:Neutrophils / Q000166:cytology; D012377:Rodentia; D013264:Stifle / Q000166:cytology; D013582:Synovial Fluid / Q000737:chemistry / Q000166:cytology
keywords: Joint; nondomestic animal; stifle; synovia