骨质疏松显微骨折早期发生发展过程的实验研究

Experimental study of osteoporotic microsurgery fractures in the early development process

目的通过比较骨转换标志物、组织病理切片、Micro CT重建及骨小梁参数,分析早期骨质疏松骨小梁变化情况及其显微骨折早期发生发展过程。方法将10只成年雌性山羊随机分为实验组(n=5)与对照组(n=5),实验组采取双侧卵巢切除术(OVX)+糖皮质激素干预,对照组仅切除腹腔同等质量脂肪组织。分别于造模第3、4、5个月时采静脉血检测Ⅰ型前胶原氨基末端N端肽(PINP)和β-Ⅰ型胶原C端肽(β-CTX),并与术前检测结果进行比较分析。于造模第5个月处死,取相应部位骨头行组织病理切片,HE染色观察镜下骨小梁形态学改变;Micro CT扫描及三维重建,并进行骨松质骨微结构相关参数定量分析。结果骨小梁组织病理形态中实验组松质骨骨小梁数目减少、厚度变薄、间隙增宽,同时骨小梁断裂、骨微缺损情况较多,而对照组松质骨骨小梁形态学大体规整,相互连接。造模第4个月时,实验组PINP水平较造模第3个月升高12.0%,β-CTX水平升高11.7%,造模第5个月时,PINP水平较第4个月迅速下降38.0%,β-CTX水平继续升高达15.1%,对照组均无明显变化。Micro CT相关参数与对照组相比,实验组颈椎、腰椎、肱骨头、肱骨颈、股骨头、股骨颈的骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)、骨密度(BMD)均下降,BS/BV、Th.Sp均升高,且差异均有统计学意义(P<0.05)。其中BMD下降程度:腰椎(41.2%)>股骨颈(27.3%)>肱骨颈(26.2%)>颈椎(21.1%)>肱骨头(17.4%)>股骨头(10.9%);同时BV/TV下降程度:腰椎(41.2%)>股骨颈(23.3%)>肱骨颈(20%)>颈椎(18.1%)>肱骨头(17.4%)>股骨头(6.2%)。结论在OVX术+激素干预联合造模条件下,山羊自身机体代偿期约为4个月,之后机体失去代偿能力,骨吸收大于骨形成,导致骨质疏松形成,进一步导致局部显微骨折;骨质疏松及显微骨折变化程度:腰椎>股骨颈>肱骨颈>颈椎>肱骨头>股骨头。

Objective To analyze the changes of early osteoporotic trabecular bone and microsurgery fractures in the early development process by comparing with bone turnover markers,histopathological sections, bone trabecular parameters and Micro CT reconstruction respectively.Methods Ten healthy adult female goats were randomly divided into two groups: the experimental group(n=5) and the control group (n=5). The goats in experimental group received bilateral oophorectomy and glucocorticiod intervention, and the goats in control group were cut the same quality of adipose tissue in the abdomen. The N-terminal procol Ⅰ agen of type Ⅰ collagen (PINP) and β-cross linked C-telopeptide of tyⅠpe collagen (β-CTX) of both groups in venous blood were detected at the third, fourth and fifth months after modeling, and compared with the preoperative test results. All goats were killed at the fifth modeling month, the corresponding parts of bone tissue were tested by pathological section, HE staining to observe the microscopic bone trabecular morphology change, Micro CT scanning and three dimensional reconstruction,and quantitative analysis of relevent parameters about cancellous bone microstructure. Results Cancelloustrabecular bone got less, thinner, broaden, and trabecular bone breaked and lost more in experimentalgroup, which were regular and interconnected in control group. At the fourth modeling month, the PINPof experimental group increased 12.0%, β-CTX increased 11.7% compared to the third month, at the fifthmodeling month, the PINP of experimental group decreased 38.0% rapidly, β-CTX still increased 15.1%compared to the fourth month, which had no significant changes in control group. Compared with the controlgroup, Micro CT founded the BV/TV, Tb.Th, Th.N, BMD of cervical, lumbar, humeral head, humerus neck,femoral head and femoral neck decreased respectively in experimental group, BS/BV, Th.Sp increasedobviously (P<0.05). The descenting order of BMD was lumbar (41.2%)> femoral neck (27.3%)>humeralneck (26.2%)>cervical (21.1%)>humeral head (17.4%)>femoral Head (10.9%). And the descent level ofBV/TV was lumbar (41.2%)>femoral neck (23.3%)>humeral neck (20%)>cervical (18.1%)>humeral head(17.4%)>femoral Head (6.2%). Conclusions In the condition of OVX and hormone intervention joint modeling, the lose of the ability of compensation and bone resorption was greater than bone formation afterthe four months of bodies’ own compensatory period, resulting in the formation of osteoporosis and furthercausing partial microscopic fractures. The likelihood descending order of osteoporosis and microsurgeryfractures was lumbar>femoral neck>humerus neck> cervical> humerus head> femoral head.