Yan Jia-Qi, Zhang Yun, Liu Fang-Shu, Cai Ting-Ting, Tong Kang-Qiang, Zhu Can, Hu Lu-Qi, Lv Shu-Min
Department of Basic Medicine, College of Medicine, Shaoxing University, Shaoxing 312000.
Department of Pediatrics, Hangzhou Bay Hospital of Ningbo, Ningbo 315336, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2018 Jan 8;34(1):83-87. doi: 10.12047/j.cjap.5608.2018.021.
To study whether tricalcium phosphate(TCP) wear particles cause injuries of periprosthetic osteocytes in the mouse calvaria, and to explain its molecular mechanism.
Thirty six-week(ICR)male mice were randomly divided into sham group, model (TCP) group and 3-methyladenine (3-MA) group. A murine calvarial model of osteolysis was established by 30 mg of TCP wear particles implantation over the periosteum around the middle suture of calvaria in mice. On the second postoperative day, the autophagy specific inhibitor 3-MA (1.0 mg/kg) was subcutaneously injected to the calvaria in the 3-MA-treated mice every other day. After 2 weeks, blood and the calvaria were obtained. Micro-CT was used to detect bone mineral density(BMD), bone volume fraction (BVF) and porosity number. HE staining and flow cytometry were performed to analyze the viability and apoptosis of periprosthetic osteocytes. The serum levels of dentin matrix protein 1(DMP-1) and sclerostin (SOST) were determined by ELISA. The proteins expressions of DMP-1, SOST, Beclin-1 and microtuble-associated protein 1 light chain 3 (LC-3) were detected by Western blot in the calvaria osteocytes.
Compared with the sham group, the mice in the TCP group showed that a significant decrease in the viability of periprosthetic osteocytes, but obvious increases in number of osteocytes death and osteocytes apoptosis (<0.05), and in serum level and protein expression of SOST; significant decreases in serum level and protein expression of DMP-1 (<0.05), and remarkable up-regulation of autophagy-related factors beclin-1 and the conversion of LC3-Ⅱ from LC3-I in the calvaria osteocytes. Compared with TCP group, the mice in the 3-MA group showed that injuries of calvaria osteocytes were obviously aggravated, and osteocytes apoptosis was significantly increased (<0.05).
TCP wear particles can cause injuries of periprosthetic osteocytes via activation of apoptosis and autophagy, which promotes osteolysis around the prosthesis osteolysis and joint aseptic loosening.
研究磷酸三钙（TCP）磨损颗粒是否会导致小鼠颅骨假体周围骨细胞损伤，并阐明其分子机制。
将36只六周龄（ICR）雄性小鼠随机分为假手术组、模型（TCP）组和3-甲基腺嘌呤（3-MA）组。通过在小鼠颅骨中缝周围骨膜上植入30mg TCP磨损颗粒建立小鼠颅骨骨溶解模型。术后第二天，每隔一天给3-MA处理组小鼠的颅骨皮下注射自噬特异性抑制剂3-MA（1.0mg/kg）。2周后，采集血液和颅骨。采用显微CT检测骨密度（BMD）、骨体积分数（BVF）和孔隙率。进行苏木精-伊红（HE）染色和流式细胞术分析假体周围骨细胞的活力和凋亡情况。采用酶联免疫吸附测定法（ELISA）测定血清中牙本质基质蛋白1（DMP-1）和硬化蛋白（SOST）的水平。通过蛋白质免疫印迹法（Western blot）检测颅骨骨细胞中DMP-1、SOST、Beclin-1和微管相关蛋白1轻链3（LC-3）的蛋白表达。
与假手术组相比，TCP组小鼠假体周围骨细胞活力显著降低，骨细胞死亡数量和骨细胞凋亡明显增加（P<0.05），血清SOST水平和蛋白表达显著升高；血清DMP-1水平和蛋白表达显著降低（P<0.05），颅骨骨细胞中自噬相关因子Beclin-1明显上调，LC3-II从LC3-I转化显著增加。与TCP组相比，3-MA组小鼠颅骨骨细胞损伤明显加重，骨细胞凋亡显著增加（P<0.05）。
TCP磨损颗粒可通过激活凋亡和自噬导致假体周围骨细胞损伤，促进假体周围骨溶解和关节无菌性松动。
