title: Mechanical loading affects the energy metabolism of intervertebral disc cells.
abstract: Research has shown that mechanical loading affects matrix biosynthesis of intervertebral disc (IVD) cells; however, the pathway(s) to this effect is currently unknown. Cellular matrix biosynthesis is an energy demanding process. The objective of this study was to investigate the effects of static and dynamic compressive loading on energy metabolism of IVD cells. Porcine annulus fibrosus (AF) and nucleus pulposus (NP) cells seeded in 2% agarose were used in this experiment. Experimental groups included 15% static compression and 0.1 and 1 Hz dynamic compression at 15% strain magnitude for 4 h. ATP, lactate, glucose, and nitric oxide (NO) contents in culture media, and ATP content in cell-agarose construct were measured using biochemical assays. While the total ATP content of AF cells was promoted by static and dynamic loading, only 1 Hz dynamic loading increased total ATP content of NP cells. Increases in lactate production and glucose consumption of AF cells suggest that ATP production via glycolysis is promoted by dynamic compression. ATP release and NO production of AF and NP cells were significantly increased by dynamic loading. Thus, this study clearly illustrates that static and dynamic compressive loading affect IVD cell energy production while cellular responses to mechanical loading were both cell type and compression type dependent.
authors.affiliation: Stem Cell and Mechanobiology Laboratory, Department of Biomedical Engineering, College of Engineering, University of Miami, Coral Gables, Florida 33146-0621, USA.
authors.forename: Hanan N
authors.initials: HN
authors.lastname: Fernando
authors.forename: Jessica
authors.initials: J
authors.lastname: Czamanski
authors.forename: Tai-Yi
authors.initials: TY
authors.lastname: Yuan
authors.forename: Weiyong
authors.initials: W
authors.lastname: Gu
authors.forename: Abdi
authors.initials: A
authors.lastname: Salahadin
authors.forename: Chun-Yuh Charles
authors.initials: CY
authors.lastname: Huang
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D019149:Bioreactors; D002470:Cell Survival / Q000502:physiology; D019245:Compressive Strength / Q000502:physiology; D003470:Culture Media / Q000494:pharmacology; D004734:Energy Metabolism / Q000502:physiology*; D005109:Extracellular Matrix / Q000378:metabolism / Q000502:physiology; D005947:Glucose / Q000493:pharmacokinetics; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D012685:Sepharose / Q000494:pharmacology; D034421:Sus scrofa; D016474:Weight-Bearing / Q000502:physiology*
chemical_list: D003470:Culture Media; D009569:Nitric Oxide; D000255:Adenosine Triphosphate; D012685:Sepharose; D005947:Glucose