骨质疏松症大鼠腰椎不同区域骨微结构变化的研究

A study on the changes of bone microstructure in different regions of the lumbar spine in rats with osteoporosis

目的基于Micro-CT方法探讨去卵巢手术(OVX)所致骨质疏松症大鼠腰椎不同区域骨量和骨微结构的差异。方法选用30只3月龄雌性SD大鼠,随机分为基础组、假手术组(Sham)和OVX组,分别在手术当天、手术后3月(3M)、手术后6月(6M)取第5腰椎,采用Micro-CT方法分析其远端、中部、近端、整体区域的骨量和骨微结构变化。结果(1)各组大鼠骨量和骨微结构的动态变化:Sham组大鼠各区域(除3M近端区域)BMD、BV/TV均随着时间明显增加(P<0.01,P<0.05),远端、近端、整体区域Tb.Th随着时间均明显增加(P<0.01),而中部区域Tb.N明显增多(P<0.05)。OVX组大鼠各区域(除3M近端区域)BMD、BV/TV均随时间显著降低(P<0.01,P<0.05)。OVX 3M,各区域Tb.N均较基础组明显减少(P<0.01,P<0.05),远端、中部、整体区域Tb.Sp均明显升高(P<0.01,P<0.05);OVX 6M,各个区域Tb.N明显减少(P<0.01),Tb.Sp明显升高(P<0.01,P<0.05),中部区域Tb.Th明显降低(P<0.05)。(2)OVX大鼠骨量和骨微结构变化的敏感性分析:OVX 3M,除近端外的3个区域BMD和BV/TV与Sham组相比均显著减少(P<0.01),远端、整体区域Tb.Th明显减少(P<0.05),远端、中部、整体区域Tb.N明显下降(P<0.01)、Tb.Sp明显升高(P<0.01,P<0.05);OVX 6M,各区域BMD和BV/TV与Sham组相比均显著减少(P<0.01),Tb.Th、Tb.N均明显下降(P<0.05,P<0.01),Tb.Sp明显升高(P<0.01)。结论在骨质疏松不同阶段,腰椎不同区域骨量和骨微结构变化趋势相同,但各指标变化的敏感性不同:骨质疏松后期各个区域均可以独立设为分析区域,但在早期选择远端区域或者整体区域更为合适。考虑分析操作方法的难易程度等因素,建议选择腰椎远端区域作为OVX所致骨质疏松症大鼠的分析区域。

Objective To investigate whether there are differences in the bone mass and microstructure of the lumbar vertebrae in different regions of osteoporosis rats induced by ovariectomy(OVX)based on micro-CT.Methods Thirty female SD rats were randomly divided into basic group,Sham group,and OVX group.The 5th lumbar vertebrae were taken on the day of surgery,3 months(3M)after surgery,and 6 months(6M)after surgery.Micro-CT was used to analyze the bone mass and microstructure changes in the distal,middle,proximal,and whole regions.Results①Dynamic changes in bone microstructure of rats in each group:BMD and BV/TV in all regions(except for the 3M proximal region)of Sham group rats increased significantly over time(P<0.01,P<0.05),Tb.Th in the distal,proximal,and whole regions increased significantly over time(P<0.01),and Tb.N in the middle region increased significantly(P<0.05).In OVX rats at 3M and 6M,BMD and BV/TV significantly decreased over time in all regions(except for the 3M proximal region,P<0.01,P<0.05).Rats of OVX 3M showed a significant decrease in Tb.N in all regions compared to those in the basic group(P<0.01,P<0.05).Tb.SP in the distal,middle,and whole regions increased significantly(P<0.01,P<0.05).Rats of OVX 6M showed a significant decrease in Tb.Th in the middle region,compared to those in the basic group(P<0.05),a significant decrease in Tb.N in each region(P<0.01),and a significant increase in Tb.Sp(P<0.01,P<0.05).②Sensitivity analysis of bone microstructure changes in OVX rats:In rats of OVX 3M,except for the proximal region,BMD and BV/TV in the other three regions reduced significantly compared to those in the Sham group(P<0.01).Tb.Th of OVX rats in the distal and whole regions reduced significantly compared to those in the Sham group(P<0.05).Tb.N of OVX rats in the distal,middle,and whole regions reduced significantly(P<0.01)and Tb.Sp significantly increased(P<0.01,P<0.05).In rats of OVX 6M,BMD and BV/TV in all regions reduced significantly compared to those in the Sham group(P<0.01).Tb.Th and Tb.N in OVX rats in all four regions reduced significantly compared to those in the Sham group(P<0.05,P<0.01).Tb.Sp increased significantly(P<0.01).Conclusion At different stages of osteoporosis,the trend of bone mass and bone microstructure changes is the same in different regions,but the sensitivity of each indicator change is different.In the later stages of osteoporosis,each region can be set as the analysis area.However,in the early stage,it is more appropriate to choose the distal region or the overall region.Considering factors such as the difficulty of analyzing operational methods,it is recommended to choose the distal region as the analysis area for osteoporosis rats induced by OVX.