title: Primary immune system responders to nucleus pulposus cells: evidence for immune response in disc herniation.
abstract: Although intervertebral disc herniation and associated sciatica is a common disease, its molecular pathogenesis is not well understood. Immune responses are thought to be involved. This study provides direct evidence that even non-degenerated nucleus pulposus (NP) cells elicit immune responses. An in vitro colony forming inhibition assay demonstrated the suppressive effects of autologous spleen cells on NP cells and an in vitro cytotoxicity assay showed the positive cytotoxic effects of natural killer (NK) cells and macrophages on NP cells. Non-degenerated rat NP tissues transplanted into wild type rats and immune-deficient mice demonstrated a significantly higher NP cell survival rate in immune-deficient mice. Immunohistochemical staining showed the presence of macrophages and NK cells in the transplanted NP tissues. These results suggest that even non-degenerated autologous NP cells are recognized by macrophages and NK cells, which may have an immunological function in the early phase of disc herniation. These findings contribute to understanding resorption and the inflammatory reaction to disc herniation.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. murai.mane@jichi.ac.jp
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Murai
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sakai
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Tomoko
authors.initials: T
authors.lastname: Nakai
authors.forename: Takashi
authors.initials: T
authors.lastname: Igarashi
authors.forename: Norimasa
authors.initials: N
authors.lastname: Seo
authors.forename: Takashi
authors.initials: T
authors.lastname: Murakami
authors.forename: Eiji
authors.initials: E
authors.lastname: Kobayashi
authors.forename: Joji
authors.initials: J
authors.lastname: Mochida
mesh_terms: D000818:Animals; D016923:Cell Death; D002470:Cell Survival; D003114:Colony-Forming Units Assay; D007107:Immune System / Q000166:cytology* / Q000276:immunology*; D007150:Immunohistochemistry; D007403:Intervertebral Disc / Q000276:immunology* / Q000473:pathology* / Q000637:transplantation; D007405:Intervertebral Disc Displacement / Q000276:immunology* / Q000473:pathology; D051379:Mice; D051381:Rats; D051598:Whole Body Imaging