title: Ionic and biochemical characterization of bovine intervertebral disk.
abstract: Intervertebral disks have been associated with low back pain, and many therapies have been proposed for its treatment. The cellular and molecular knowledge of intervertebral disks composition and precise methods to quantify disk components are important for any type of proposed therapy. Thus, the aim of this study was to correlate glycosaminoglycans presence with the quantitation of cells, ions and collagen fiber distributions in different intervertebral disk sections.
  
  
  
  In total, 14 intervertebral disks were used from cattle. All of the disks were dehydrated, separated in seven sections and digested in sodium-free papain buffer. Glycosaminoglycan measurements were performed in the samples according to agarose electrophoresis method; total cells were measured using the PicoGreen® technique, ions were quantified, and collagen fiber birefringence was analyzed with polarized light.
  
  
  
  Cations Na+ and K+ are more concentrate in the nucleus (Na(+) = 1688.50 ± 110 mmol/L; K(+) = 111.9 ± 28 mmol/L) of intervertebral disks than the annulus (Na(+) = 652.80 ± 75 mmol/L; K(+) = 55.6 ± 8 mmol/L). A negative correlation between cells number and sodium/potassium was observed (p < 0.001) Additionally, thin collagen fibers were largest in the nucleus, similar to hyaluronate distribution.
  
  
  
  The results suggest that annulus fibrosus cells are also sensitive to changes in ionic concentrations such as nucleus pulposus cells. Additionally, hyaluronate is related to thin collagen fibers type II.
authors.affiliation: a Department of Orthopaedics and Traumatology, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Delio Eulalio
authors.initials: DE
authors.lastname: Martins
authors.affiliation: b Department of Biochemistry , Universidade Federal de Juiz de Fora , Minas Gerais , Brazil.
authors.forename: Valquiria Pereira
authors.initials: VP
authors.lastname: Medeiros
authors.affiliation: c Department of Biochemistry, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Gabriela Feitosa
authors.initials: GF
authors.lastname: Demerov
authors.affiliation: c Department of Biochemistry, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Camila Melo
authors.initials: CM
authors.lastname: Accardo
authors.affiliation: c Department of Biochemistry, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.|d Centro Interdisciplinar de Investigacao Bioquimica , Universidade de Mogi das Cruzes , Mogi das Cruzes , Brazil.
authors.forename: Edgar Julian
authors.initials: EJ
authors.lastname: Paredes-Gamero
authors.affiliation: a Department of Orthopaedics and Traumatology, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Wajchenberg
authors.affiliation: e Department of Morphology and Genetics, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Rejane Daniele
authors.initials: RD
authors.lastname: Reginato
authors.affiliation: c Department of Biochemistry, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Helena Bonciani
authors.initials: HB
authors.lastname: Nader
authors.affiliation: a Department of Orthopaedics and Traumatology, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Eduardo Barros
authors.initials: EB
authors.lastname: Puertas
authors.affiliation: a Department of Orthopaedics and Traumatology, Escola Paulista de Medicina , Universidade Federal de São Paulo , São Paulo , Brazil.
authors.forename: Flávio
authors.initials: F
authors.lastname: Faloppa
mesh_terms: D000818:Animals; D002412:Cations / Q000378:metabolism*; D002417:Cattle; D002809:Chondroitin Sulfates / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism*; D006820:Hyaluronic Acid / Q000378:metabolism; D007403:Intervertebral Disc / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism
chemical_list: D002412:Cations; D006025:Glycosaminoglycans; D006820:Hyaluronic Acid; D002809:Chondroitin Sulfates; D003094:Collagen; D012964:Sodium; D011188:Potassium
keywords: Collagen; glycosaminoglycans; hyaluronic acid; intervertebral disk; potassium; sodium