Jiang Ai, Gao Shan, Zhao Zhenda, Tan Qizhao, Sun Shang, Song Chunli, Leng Huijie
Department of Orthopaedics, Peking University Third Hospital, Beijing 100191, China.
Beijing Key Lab of Spine Diseases, Beijing 100191, China.
Ann Transl Med. 2020 Apr;8(7):476. doi: 10.21037/atm.2020.03.93.
Osteoarthritis (OA) is prevalent in postmenopausal women. Subchondral bone in ovariectomized (OVX) rats might play a more important role in cartilage degeneration compared with other types of OA. How subchondral osteoblast changes in OVX rats is still unclear. Understanding of osteoblast changes obtained from OVX subchondral bone might be helpful to clarify pathogenesis of OVX-OA.
Female Sprague-Dawley rats were randomly divided into two groups: Sham (n=20) and OVX (n=20). Serum levels of Alkaline phosphatase (ALP) and C-telopeptide of type I collagen (CTX-I) were measured every one or two weeks. All rats were executed at week 9 post surgery. The weight of rats and the wet weight of uterus were assessed. Micro-computed Tomography (micro-CT) was used to analyze the knee microstructure, and toluidine blue staining was employed to evaluate cartilage erosion. Subchondral osteoblast proliferation ability by cell counting kit-8 assay, osteogenic genes expressions by reverse transcription polymerase chain reaction (RT-PCR), differentiation and mineralization ability by ALP staining and alizarin red staining were evaluated and compared between Sham and OVX.
Ovariectomy induced significant increases of serum ALP and CTX-I as early as at week 2. At week 9 after surgery, the body weight of OVX rats was significantly increased, and uterus weight of OVX rats was remarkably decreased. OVX rats demonstrated significant subchondral bone change and cartilage erosion compared with Sham rats. mRNA levels of early markers of osteogenic differentiation (ALP, type I collagen, Runx2) were enhanced in OVX rats, but the late marker (osteocalcin) was not significantly different. ALP activity of osteoblasts increased, but the mineralization capacity decreased in OVX rats.
Subchondral osteoblasts in OVX rats exhibited different proliferation, differentiation and mineralization abilities from normal counterparts.
骨关节炎（OA）在绝经后女性中很常见。与其他类型的OA相比，去卵巢（OVX）大鼠的软骨下骨在软骨退变中可能起更重要的作用。OVX大鼠软骨下成骨细胞如何变化仍不清楚。了解从OVX软骨下骨获得的成骨细胞变化可能有助于阐明OVX-OA的发病机制。
将雌性Sprague-Dawley大鼠随机分为两组：假手术组（n=20）和OVX组（n=20）。每1或2周测量血清碱性磷酸酶（ALP）和I型胶原C末端肽（CTX-I）水平。所有大鼠在术后第9周处死。评估大鼠体重和子宫湿重。采用微型计算机断层扫描（micro-CT）分析膝关节微观结构，并用甲苯胺蓝染色评估软骨侵蚀情况。通过细胞计数试剂盒-8法评估软骨下成骨细胞增殖能力，通过逆转录聚合酶链反应（RT-PCR）检测成骨基因表达，通过ALP染色和茜素红染色评估分化和矿化能力，并在假手术组和OVX组之间进行比较。
去卵巢早在第2周就导致血清ALP和CTX-I显著升高。术后第9周，OVX大鼠体重显著增加，子宫重量显著降低。与假手术大鼠相比，OVX大鼠表现出显著的软骨下骨改变和软骨侵蚀。成骨分化早期标志物（ALP、I型胶原、Runx2）的mRNA水平在OVX大鼠中升高，但晚期标志物（骨钙素）无显著差异。OVX大鼠成骨细胞的ALP活性增加，但矿化能力降低。
OVX大鼠的软骨下成骨细胞表现出与正常成骨细胞不同的增殖、分化和矿化能力。
