The Experimental Study :glucocorticoid Intervene Early The Procession Of The Intervertebral Disc Degeneration By Regulating The AQP-3、MMP-3

Objective: The purpose of this experiment is to make model of the rabbit intervertebral discdegeneration. After the successful establishment of the animal model four weeks, eight weeks,We only select four weeks of an animal model of intervertebral disc degeneration to injectdexamethasone. When dexamethasone was injected in intervertebral disc degeneration, weobserve whether the dexamethasone intervene the disc early degeneration by regulatingexpression of AQP-3, MMP-3.Methods: 18 clean and healthy 6-month-old New Zealand white rabbits were randomlydivided into three groups for the establishment of the rabbit disc degeneration model. Underdirect vision with a 16G needle syringe and needle angle with the center line about 45°,intervertebral disc (L2/3.L3/4.L4/5.L5/6)were pierced by the side of annulus and paralleledcartilage endplate, and the depth was controlled at 5 mm, and stayed 5s. After making model offour weeks、eight weeks, we take examine in rabbit intervertebral disc by x-ray, magneticresonance imaging, histopathology to sure disc degeneration. 12 New Zealand white rabbits (48discs) and L2/3.L3/4.L4/5.L5/6 on behalf of each rabbit’s normal control group, the degenerationof the control group, experimental group A, experimental group B. Degeneration of the controlgroup, experimental group A, experimental group B were injected with normal saline0.1ml ,dexamethasone 2.5mg/0.1ml, dexamethasone 5mg/0.1ml. After three days, seven daysinjection of dexamethasone, taking the nucleus pulposus specimens were detected by RT-PCRand immunohistochemical to expression of AQP-3 and MMP-3. The above data were analyzed,how dexamethasone is to influence the expression of MMP-3 and expression of AQP-3 indegeneration of the nucleus pulposus cells.Results: After intervertebral disc degeneration animal models was made with No. 16 needle infour weeks、eight weeks, we take examine in rabbit intervertebral disc x-ray, magnetic resonanceimaging, histopathology to sure disc degeneration, and as the degree of degeneration in graduallyincreased over time. After 4 weeks，8 weeks in CR tablets, DHI show statistically significantdifference (P <0.05); According to Pfirrmann grading , after 4 weeks, 8 weeks, 12 weeks onmagnetic resonance imaging, Three time points show statistically significant (P <0.05). In thePCR results, both MMP-3 and AQP-3 are show significant statistically difference (P <0.05), butonly are MMP-3 express positive result in immunohistochemistry.Conclusion: According to this experimental results, we learned that the rabbit disc degenerationmodel can be established by the use of 16G needle through the annulus fibrous in four week .Four weeks of animal models of intervertebral disc degeneration (early degeneration), theMRI T2-weighted images showed low signal compared to other disc，and Pfirrmann gradingwere less than three. At this stage, Using of 5mg/0.1ml dexamethasone in ten days later, MRIT2-weighted signal gradually increased compare to other disc. 5mg/0.1ml Dexamethasone canincrease the expression of AQP-3 expression in seven days better than three days. what’s more,dexamethasone could inhibit the expression of MMP-3, and in MMP-3content is graduallyreduced with the passage of time.