Expression Of Cadherin-β-catenin Complex In The In Vivo Rabbit Endplate Cartilage By Tension Load

Objective: To develop the degeneration model by tension induced in vivo rabbitintervertebral disc and to investigate the expression level of Cadherin-β-Catenin complexvarious subunits and its significance in the cartilage endplate degeneration process.Method: New Zealand white rabbits with six months old were randomly divided into threegroups: blank control group, tension model group and non stress loading group. Blankcontrol group obtained L4/5intervertebral disc at0day. we used the intervertebral discassistor to fix L4and L5vertebral body in tension model group and non stress loadinggroup. The L4/5intervertebral disc of tension model group were exerted2.4MPa axialtension force, non stress loading group were only installed assistor but not exerted tensionforce, this two groups to obtain L4/5intervertebral disc at28,56days. Intervertebral discmorphological handled by HE staining.NBT/DAPI staining was used to observeintervertebral disc cell survival rate in each time period. The gene expression level ofaggrecan,type Ⅱ collagen,E-Cadherin and β-Catenin were examined by Real-time RT-PCRin each time period. The protein expression of E-Cadherin and β-Catenin were examined byWestern blot in each time period.Results: The tissue morphology, cell survival rate and expression level of aggrecan,type Ⅱcollagen,E-Cadherin and β-Catenin between non stress loading group and blank controlgroup had not significant difference. Comparison with the blank control group and non stressloading group, the tension model group with the increase of tension load time, intervertebraldisc living cells percentage had no obvious change. and the annulus fibrosus arrangedgradually become chaotic, nucleus pulposus were dehydration and deflation, and thenotochord cells vacuoles tissues tend to disappeared. Aggrecan and type Ⅱcollagen mRNAexpression were obviously reduced. Both the mRNA and protein products of E-cadherin were significantly decreased,and β-catenin expression were obviously up-regulated..Conclusion: In vivo rabbit intervertebral disc can appear degeneration gradually withstrength the extension of time. In the process of disc degeneration by tension loads induced,the tension load can lead to the E-cadherin expression decline and β-catenin upregulationin endplate cartilage. Tension load induced endplate cartilage degeneration may be throughregulating the E-cadherin-β-catenin complexus, E-cadherin and β-catenin expression inintervertebral disc may be lead to remit or even block the endplate cartilage degeneration.Our project will further uncover the pathology of intervertebral disc degeneration, which willprovide a new approach for the research and treatment of this disorder.