氯化锂对去卵巢骨质疏松大鼠骨微结构和骨髓基质细胞分化的影响

Lithium chloride effects on bone microarchitecture and bone marrow stromal cell differentiation of ovariectomized osteoporosis rats

背景:骨质疏松是一种好发于绝经后妇女的慢性骨代谢疾病,随着世界人口老龄化的增加,如何预防和治疗绝经后骨质疏松是目前困扰医疗界的一大难题。目的:探讨氯化锂对去卵巢骨质疏松大鼠骨微结构和骨髓基质细胞分化的影响。方法:将30只3月龄雌性健康未孕SD大鼠去卵巢,因2只大鼠由于感染死亡,将剩下28只大鼠随机分为去卵巢体内组(9只)、去卵巢体外组(10只)和氯化锂组(9只)。手术后第11周,氯化锂组按照体质量每周腹腔注射3次氯化锂,剂量为15 mg/kg,干预8周后,用micro-CT检测9只去卵巢体内组和9只氯化锂组大鼠左侧股骨的骨微结构。10只去卵巢体外组大鼠的双侧股骨和胫骨用于骨髓基质细胞的培养,接种24 h后加入氯化锂,分为0 mmol/L(对照组)、1 mmol/L组和5 mmol/L组,培养至第6天和第8天更换培养基并加入相应浓度氯化锂,培养第10天处理细胞,用Western blot检测其SP7、Runx2和PPARγ2蛋白的表达水平。结果与结论:1体内结果表明,氯化锂组体积骨密度、骨体积分数和骨小梁数目显著高于去卵巢体内组,骨小梁间隙显著低于去卵巢体内组,而骨小梁厚度和结构模型指数无显著变化。2体外结果表明,1 mmol/L和5 mmol/L氯化锂组骨髓基质细胞Sp7和Runx2蛋白表达水平显著高于对照组,而PPARγ2蛋白表达水平显著低于对照组。3以上实验结果表明,氯化锂可能是通过促进去卵巢骨质疏松大鼠骨髓基质细胞向成骨分化而改善去卵巢骨质疏松大鼠的骨微结构。

BACKGROUND： Osteoporosis is a bone metabolic disease that affects women more than men. Prevention and treatment of osteoporosis is becoming a serious medical problem because of the aging of the population. OBJECTIVE： To explore the effects of lithium chloride treatment on bone microarchitecture and bone marrow stromal cell differentiation of ovariectomized osteoporosis rats. METHODS： After ovariectomy, 28 of 30 healthy female Sprague-Dawley rats, 3 months old, were randomly divided into the following three groups： ovariectomized in vivo group（9 rats）, ovariectomized in vitro group（10 rats）, and lithium chloride group（9 rats）. At the 11 th week postoperatively, rats in the lithium chloride were intragastrically injected with lithium chloride at a dose of 15 mg/kg, three times per week. After 8 weeks of treatment, the bone microarchitectures of the rat left femur in the ovariectomized in vivo group and lithium chloride group were detected by micro-CT. The bone marrow mesenchymal stem cells were freshly isolated from the bone marrow of the bilateral femurs and tibia of rats in the ovariectomized in vitro group. After 24 hours ofinoculation, the cells were cultured in lithium chloride and divided into 0 mmol/L（control）, 1 mmol/L and 5 mmol/L groups. At 6 and 8 days of culture, the medium was changed and lithium chloride with the corresponding concentrations was added. At 10 days of culture, western blot assay was adopted to detect protein expression of Runx-2, SP7 and PPARγ2. RESULTS AND CONCLUSION：（1） Compared with the ovariectomized in vivo group, the volume density of trabecular bone, number of trabecular bone, and bone volume fraction in the lithium chloride group were significantly increased and the separation of trabecular bone was significantly decreased. However, no differences were seen in the thickness of trabecular bone and structure model index.（2） Lithium chloride at 1 and 5 mmol/L could increase the protein expression of Sp7 and Runx-2 in bone marrow stromal cells, but decrease the protein expression of PPARγ2. These results indicate that lithium chloride may improve the microarchitecture of the trabeculr bone in ovariectomized osteoporosis rats through stimulating the osteogenic differentiation of bone marrow stromal cells.