The Expression Of IL-1β,CD34 And Their Significance In The Intervertebral Disc Degeneration Of Subcutaneous Nicotine Injection Of Rats

Part I:The establishment of a model of the intervertebral disc degeneration of subcutaneous nicotine injection of rats[Objective]:To observe the effect of subcutaneous nicotine injection to the intervertebral discs of Sprague - Dawle (SD) rats.[Methods]:We randomly divided 30 10-11 weeks male SD rats into three groups, weight 250- 350g, which were from the same batch but different brood. Group 1 were control group, group 2,3 were experimental groups, each group had 10. Group 1 were injected subcutaneously saline 1.5 ml/kg every day. Group 2 were injected subcutaneously nicotine 3mg/kg every day, volume was 1.5 ml/kg, injected for 2 weeks. Group 3 were injected subcutaneously nicotine 3mg/kg every day, volume was 1.5 ml/kg, injected for 8 weeks. At the scheduled time,40mg/kg sodium pentobarbital were injected intraperitoneal, removed the spine, and use small sharp knife and ophthalmic scissors to excise the L4/L5 intervertebral discs, then fixed, demineralization, did paraffin section. HE staining was used to check the histological changes.[Results]:(1) Control group:The structures of intervertebral discs were clear, the levels and collagen fiber were well, annulus fibrosus and the nucleus pulposus jointed compactly, the boundaries were clear. Chondrocytes and matrix were rich in nucleus pulposus, cartilage endplates were continuous, cartilage endplates and vertebraes jointed compactly. (2) Injected nicotine for 2 weeks group:There were not obvious changes in intervertebral disc compared with the control group, a few annulus fibrosus were slight degeneration. (3) Injected nicotine for 8 weeks group:The structure of intervertebral disc annulus fibrosus were disorder, most of the intervertebral disc annulus fibrosus were severe distortion, a few were seriously backward folded, local annulus fibrosus were lack,60% were grade 3 degeneration, 40% were grade 4 degeneration, annulus fibrosus and nucleus pulposus were ruptured, chondrocytes and matrix were reduced even lack in nucleus pulposus, cartilage endplates were discontinuous,cartilage endplate and vertebrae did not joint compactly.[Conclusion]:Subcutaneous nicotine injection is accurate, safe and convenient, can be used in the preparation of animal model of intervertebral disc degeneration, and the extent of intervertebral disc degeneration is positively correlated with the time of nicotine injection. Part II:The expression of IL-1β,CD34 and their significance in the intervertebral disc degenera,tion of subcutaneous nicotine injection of rats[Objective]:To research the expression of IL-1β,CD34 after the establishment of a model of the intervertebral disc degeneration of Subcutaneous nicotine injection of rats.[Methods]:After the establishment of a model of the intervertebral disc degeneration of subcutaneous nicotine injection of rats, excised the L4/L5 intervertebral discs, then fixed, demineralization, did paraffin section. IL-1β,CD34 were examined by using immunohistochemical staining.[Results]:(1) Control group:The rate of IL-1βpositive-staining cells was (7.0±0.34)%. Nicotine injection for 2 weeks group:The rates of IL-1βpositive-staining cells was (32.1±2.69)%. Nicotine injection for 8 weeks group:The rate of IL-1βpositive-staining cells was (78.6±2.59)%. Use SPSS16.0 to compare these three groups, P< 0.05, all had differences. (2) CD34 staining to observe the capillaries in cartilage endplates. Control group:There were 23.6±2.37capillaries in the cartilage endplates. Nicotine injection for 2 weeks group:There were 20.0±2.00 capillaries in the cartilage endplates. Nicotine injection for 8 weeks group:There were 9.9±1.73 capillaries in the cartilage endplates. Use SPSS 16.0 to compare these three groups, P< 0.05, all had differences.[Conclusion]:With the extension of nicotine injection, the rats of IL-1βpositive-staining cells were increasing gradually, but the capillaries in the cartilage endplates were gradually reduced. IL-1βover-active and the reduced of capillaries in cartilage endplates may cause intervertebral disc degeneration.