title: Aquaporin-1: a potential membrane channel for facilitating the adaptability of rabbit nucleus pulposus cells to an extracellular matrix environment.
abstract: BACKGROUND
  During the process of degenerative aging of the intervertebral disc (IVD), the extracellular matrix (ECM) environment changes, with osmolarity and oxygen (O(2)) concentration important components of such changes. The IVD cells respond to maintain the homeostasis and function of the IVD by several mechanisms. Aquaporin-1 (AQP-1) is a transmembrane channel protein that is permeable to water and O(2), which prevents rapid volume deformation under osmotic stress and facilitates O(2) diffusion across the plasma membrane. One hypothesis is that AQP-1 has potential roles in aging degeneration of IVDs.
  
  
  METHODS
  In this study, AQP-1 expression levels were investigated in aging rabbit nucleus pulposus (NP) cells using immunohistochemistry and Western blotting in vivo, and different osmolarities and O(2) concentrations in vitro by quantitative real-time PCR.
  
  
  RESULTS
  The results showed that AQP-1 was expressed at different levels in aging rabbit's NPs and AQP-1 was regulated by the NP cells in different ECM environmental conditions. AQP-1 was downregulated under hypo-osmotic stress to prevent rapid swelling deformation and was upregulated under hypoxic stress to facilitate O(2) utilization.
  
  
  CONCLUSIONS
  It is suggested that AQP-1 may reflect the status of aged IVDs and have a potential role in reflecting the adaptability of NP cells under different adverse ECM environments in aging degenerated IVDs.
authors: Department of Orthopaedics, The First Hospital of China Medical University, No. 155 Nanjingbei Road, Heping District, Shenyang 110001, People's Republic of China.
authors: Feng
authors: F
authors: Wang
authors: Yue
authors: Y
authors: Zhu
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000818:Animals; D051398:Aquaporin 1 / Q000096:biosynthesis / Q000235:genetics*; D015153:Blotting, Western; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000378:metabolism* / Q000473:pathology; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry; D055959:Intervertebral Disc Degeneration / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007473:Ion Channels / Q000378:metabolism*; D008159:Lumbar Vertebrae; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics*; D011817:Rabbits
chemical_list: D007473:Ion Channels; D051398:Aquaporin 1; D012313:RNA