The Expression And Possible Significance Of MTOR Protein Induced By Cyclic Pressure In Endplate Chondrocytes

Objective: To investigate the expression and possible significance of mTOR proteinin organ culture model of rabbit intervertebral disc.Methods:36New Zealand white rabbits which were6months old were randomlydivided into cyclic mechanical pressure group and control group.The animals wereinfused with1.3ml of heparin(5000U/mL) intravenously before were killed. Rabbitsintervertebral disc were taken out completely with part of the vertebrae from lumbarspines by asepsis.The whole rabbit intervertebral discs were cultured in medium with20%fetal bovine serum supplemented.And cyclic mechanical pressure at0.2MPa wasapplied for different periods,once every30minutes in a day.The change ofhistomorphology, extracellular matrix, the mRNA and protein expression levels ofaggrecan, typeⅡcollagen, mTOR gene within intervertebral disc tissue wereassessed by HE stainin, Safranin-O stain,Real-time PCR and Western-blotting atdifferent periods both control group and cyclic mechanical pressure group.Results: Compared with0day group,there are showed minimal changes in histomorp-hology,extracellular matrix,cell viability and the mRNA and protein expression levelsof aggrecan,typeⅡcollagen at control group for7day..there are showed minimalchanges in histomorphology at cyclic mechanical pressure for7days.there are showedobvious change of damage in histomorphology both control group and cyclicmechanical pressure group for14days.there are showed obvious change of damage inextracellular matrix both control group for14days and cyclic mechanical pressuregroup for7,14days.the expression level of typeⅡcollagen,aggrecan gene weresignificantly decreased at7,14days of cyclic mechanical pressure group and14daysof control group.With the extension of the pressure time, the result of mTOR protein which is consistent with the genetic level test is increased.Conclusion: Regulating mTOR may alleviate or even block the endplate cartilagedegeneration, and thus provide a new target for the prevention and treatment ofintervertebral disc degeneration.