| Objectives The model of ovariectomy combined with spinal fusion was established in rats and then Simvastatin intervention was given to explore the effect of Simvastatin on the adjacent segment disc degeneration after ovariectomy combined with spinal fusion.Methods 60 female 3-month-old rats were randomly divided into Sham group,OVX group,PLF group,OVX+PLF group and OVX+PLF+Sim group.OVX and PLF were performed at the beginning of the experiment and 4 weeks later and the Sim treatment time was 12 weeks.After the end of the experiment,spinal X-ray was taken of the rats undergoing PLF,and the fusion site was scored by X-ray.After that,the rats were sacrificed and the effects of spinal fusion were evaluated by spinal manipulation at L3-L6 segments.The microstructural index of bone tissue in L6 vertebral body were analyzed by Mirco-CT.The intervertebral discs and vertebral bodies at L5-L6 levels were decalcified,embedded and sectioned and the degree of degeneration of intervertebral discs at adjacent segments was observed by HE staining and histological score was performed.The expression levels of Aggrecan,Col-Ⅱ,and ADAMTS-4 in the nucleus pulposus of intervertebral disc were analyzed by immunohistochemistry.Results 1 Evaluation results of L4-L5 intervertebral disc fusion:(1)Manual evaluation results: L4-L5 fusion segment is stable and has no obvious activity in PLF group,OVX+PLF group and OVX+PLF+Sim group;(2)X-ray score of the fusion segment: the score of the OVX+PLF group was significantly higher than that of the PLF group(P<0.05).2.The results of Mirco-CT of L6 vertebral bodies showed BMD,Tb.N and BV/TV in Sham group were significantly higher than those in OVX group and OVX+PLF group(P<0.05);Tb.SP was on the opposite side(P<0.05).BMD,BV/TV and Tb.N in OVX group were lower than those in PLF group(P<0.05);BMD of OVX group and PLF group was higher than that of OVX+PLF group(P<0.05);BV/TV and Tb.N in PLF group were significantly higher than those in OVX+PLF group(P<0.05)and Tb.SP was on the opposite side(P<0.05).BMD,BV/TV and Tb.N in simvastatin intervention group were significantly higher than those in OVX+PLF group(P<0.05)and Tb.SP was the opposite side(P<0.05).3.HE staining of adjacent intervertebral discs: Compared with the Sham group,PLF group,OVX group and OVX+PLF group all showed significant histological degeneration and the simvastatin treatment group showed certain improvement compared with the OVX+PLF group.4.Histological score: The score of model group was significantly higher than that of Sham group(P<0.05);The score of OVX+PLF group was significantly higher than that of OVX group and PLF group(P<0.05).The score of simvastatin treatment group was significantly lower than that of OVX+PLF group(P<0.05).5 Immunohistochemical staining results showed that :(1)ADAMTS-4:OVX group was significantly higher than that of Sham group(P<0.05);IOD value of OVX+PLF group was significantly higher than that of Sham group,OVX group and PLF group(P<0.05).IOD in simvastatin group was significantly lower than that in OVX+PLF group(P<0.05).(2)COI-Ⅱ: The IOD value of OVX group was significantly lower than that of Sham group(P<0.05)and the IOD value of OVX+PLF group was significantly lower than that of PLF group(P<0.05).(3)Aggrecan: IOD value of OVX+PLF group was significantly lower than that of Sham group,OVX group and PLF group(P<0.05)and IOD value of simvastatin group was significantly higher than that of OVX+PLF group(P<0.05).Conclusions 1 Ovariectomy-induced osteoporosis and spinal fusion can both act as a single inducer for disc degeneration.2 The combination of the two modeling methods aggravates the degeneration of adjacent segments.3 Simvastatin intervention can reduce the degree of intervertebral disc degeneration in adjacent segments to a certain extent.Figure 14;Table 2;Reference 127... |
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