title: Nerve growth factor of cultured medium extracted from human degenerative nucleus pulposus promotes sensory nerve growth and induces substance p in vitro.
abstract: METHODS
  We investigated the mechanism of discogenic low back pain using an in vitro model.
  
  
  OBJECTIVE
  To evaluate the axonal growth and induction of a painful neuropeptide, substance P (SP), using rat dorsal root ganglion (DRG) neurons and degenerated human disc cells in vitro.
  
  
  BACKGROUND
  Degeneration of the lumbar intervertebral disc is a cause of low back pain. The pathologic mechanism is thought to be sensory nerve ingrowth into the inner layers of the degenerated intervertebral disc; however, the precise patho-mechanism has not been clarified.
  
  
  METHODS
  The nucleus pulposus (NP) and annulus fibrosus (AF) of human intervertebral discs were harvested from patients with discogenic low back pain. Extracted medium from human degenerative intervertebral discs was cultured with neurons of rat DRGs. We evaluated the promotion of axonal growth and SP induction of DRG neurons in extracted medium from the NP and AF using immunocytochemistry.
  
  
  RESULTS
  The average length of growing axons in the NP and AF was significantly longer than that in the control (P < 0.005). That in the NP was significantly longer than that in the AF. The average length of growing axons in the NP was significantly shortened after anti-nerve growth factor (NGF)beta treatment (P < 0.005); however, that in the AF was not (P > 0.05). The percentage of SP-immunoreactive cells with growing axons was significantly higher only in the NP group compared with the control and AF groups (P < 0.005), and anti-NGFbeta treatment decreased the expression of SP in the NP group (P < 0.05).
  
  
  CONCLUSIONS
  Extracted medium from the NP and AF promoted axonal growth. Furthermore, NGF from the NP promoted axonal growth and induced SP. These in vitro results may suggest that NGF from the NP promotes the growth of sensory nerve fibers innervating the degenerated intervertebral disc and may induce SP related with pain transmission.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan. kazuyo@sb3.so-net.ne.jp
authors.forename: Kazuyo
authors.initials: K
authors.lastname: Yamauchi
authors.forename: Gen
authors.initials: G
authors.lastname: Inoue
authors.forename: Takana
authors.initials: T
authors.lastname: Koshi
authors.forename: Masaomi
authors.initials: M
authors.lastname: Yamashita
authors.forename: Toshinori
authors.initials: T
authors.lastname: Ito
authors.forename: Munetaka
authors.initials: M
authors.lastname: Suzuki
authors.forename: Yawara
authors.initials: Y
authors.lastname: Eguchi
authors.forename: Sumihisa
authors.initials: S
authors.lastname: Orita
authors.forename: Masashi
authors.initials: M
authors.lastname: Takaso
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Aoki
authors.forename: Nobuyasu
authors.initials: N
authors.lastname: Ochiai
authors.forename: Shunji
authors.initials: S
authors.lastname: Kishida
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Endo
authors.forename: Toshihide
authors.initials: T
authors.lastname: Yamashita
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Takahashi
authors.forename: Seiji
authors.initials: S
authors.lastname: Ohtori
mesh_terms: D000328:Adult; D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000494:pharmacology; D001369:Axons / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry* / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005727:Ganglia, Spinal / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007403:Intervertebral Disc / Q000737:chemistry*; D017116:Low Back Pain / Q000209:etiology; D008875:Middle Aged; D020932:Nerve Growth Factor / Q000276:immunology / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000502:physiology*; D013122:Spinal Diseases / Q000150:complications / Q000378:metabolism*; D013373:Substance P / Q000096:biosynthesis*
chemical_list: D000906:Antibodies; D003470:Culture Media; D011994:Recombinant Proteins; D013373:Substance P; D020932:Nerve Growth Factor