Influence of diurnal hyperosmotic loading on the metabolism and matrix gene expression of a whole‐organ intervertebral disc model

• DOI: 10.1002/jor.20243
• Publication Date: 2006-08-17T23:17:04Z
• Authors: Daniel Haschtmann; Jivko V. Stoyanov; Stephen J. Ferguson
• Keywords: Viability assay; Aggrecan; Osmotic concentration; Intervertebral Disc; Organ culture; Osmotic shock; Matrix (chemical analysis)

Abstract It is generally agreed that the mechanical environment of intervertebral disc cells plays an important role in maintaining a balanced matrix metabolism. The precise mechanism by which signals are transduced into poorly understood. Osmotic changes extracellular (ECM) thought to be involved. Current in‐vitro studies on this topic mostly short‐term and show conflicting data reaction subjected osmotic partially due heterogenous often substantially‐reduced culture systems. aim study was therefore investigate effects cyclic loading for 4 weeks metabolism gene expression full‐organ system. Intervertebral disc/endplate units were isolated from New Zealand White Rabbits cultured either iso‐osmotic media (335 mosmol/kg) or diurnally exposed 8 hours hyper‐osmotic conditions (485 mosmol/kg). Cell viability, metabolic activity, composition profile (collagen types I/II aggrecan) monitored using Live/Dead cell viability assay, tetrazolium reduction test (WST 8), proteoglycan DNA quantification assays quantitative PCR. results diurnal stimulation did not have significant content, cellularity after 28 days culture. However, hyperosmolarity caused increased death early phase counteracted up‐regulation type I collagen nucleus annulus cells. Moreover, initially decreased cellular dehydrogenase activity recovered with aggrecan down‐regulation delayed, although latter according our statistical criteria. In contrast, II respond down‐regulated both groups. conclusion, whole‐organ inhibits as encountered degenerative disease counteracts hypo‐activity. © 2006 Orthopaedic Research Society. Published Wiley Periodicals, Inc. J Orthop Res 24:1957–1966,