Establishment Of Cervical Dynamic And Static Unbalance Models And Preliminary Study On The Mechanism Of Cervical Degeneration In Rats

Objective:Cervical spondylosis is a common and severe degenerative disease among mid-aged population in modern society,which cervical degeneration is regarded as the most important risk factor for cervical spondylosis.To dynamically observe the changes of x-ray,histomorphology appearance and serum inflammatory cytokines of cervical degenerative disease induced by unbalanced dynamic and static forces in rats models and preliminarily discuss the mechanism of cervical degeneration for clinical prevention and treatment of cervical spondylosis.Methods:60 Sprague Dawley(SD)rats were randomized into model groups(n=45)and control(n=15)groups,which were randomly subdivided into three groups corresponding to 1-month,3-month and 6-month postoperation.Model groups included 10,15,20 rats at corresponding postoperative stage and control group had 5 rats at each time point.By excising cervicodorsal muscles,interspinous ligaments and supraspinous ligament of rats in model groups,cervical physiological balance was disrupted to establish unbalanced dynamic and static rat model.The control groups was just incised the skin.At corresponding postoperative stage,cervical x-ray films were acquired and intervertebral disc space and intervertebral foramen size were measured.At the same time,some serum inflammatory cytokines(interleukin-1?(IL-1?),tumor necrosis factor-a(TNF-a),interleukin-10(IL-10))of all rats were quantitatively determinated by enzyme-linked immunosorbent assay(ELISA).Finally,to observe the morphologic change of cervical intervertebral disc specimens stained with Hematoxylin-Eosin staining(HE)which were harvested after the rats being sacrificed.The results were statistically analyzed and compared among groups.Results:Compared with the control group,the cervical x-ray appearance of rats in model groups showed varying degrees of narrowing of intervertebral foramen and reduced intervertebral disc space which is statistically significant.Meanwhile,the morphologic changes of cervical intervertebral disc in model group showed varying degrees of degeneration:the outer layer of fibrous tissue denatured,thickening,with proliferation of peripheral blood vessels near the nucleus pulposus.Even some of the specimens showed the nucleus pulposus was reduced or replaced by the fiber or cartilage tissue at corresponding postoperative stage.What's more,the serum IL-1?,TNF-a and IL-10 in model groups significantly increased at 1-month and 3-month postoperation with statistically difference(P<0.05,P<0.01,P<0.001)compared with control group.Conclusions:The change of x-ray and histomorphology appearance demonstrated destruction of the dynamic and static imbalance of cervical spine could accelerate cervical degeneration,which confirmed we have successfully established cervical dynamic and static unbalance models in rats.On the other hand,the high expression of serumIL-1?,TNF-? and IL-10 may be associated with cervical disc degenaeration.