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

Guo Gai; Bu Shu-min; Chen Guan-jie

doi:10.3969/j.issn.2095-4344.2015.41.005

Abstract：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 cel differentiation of ovariectomized osteoporosis rats. METHODS:After ovariectomy, 28 of 30 healthy female Sprague-Dawley rats, 3 months old, were randomly divided into the folowing three groups: ovariectomizedin vivo group (9 rats), ovariectomizedin vitro group (10 rats), and lithium chloride group (9 rats). At the 11th week postoperatively, rats in the lithium chloride were intragastricaly 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 ovariectomizedin vivo group and lithium chloride group were detected by micro-CT. The bone marrow mesenchymal stem cels were freshly isolated from the bone marrow of the bilateral femurs and tibia of rats in the ovariectomizedin vitro group. After 24 hours of inoculation, the cels 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 ovariectomizedin 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 cels, but decrease the protein expression ofPPARγ2. 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 cels.