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Copyright of Chinese Journal of Tissue Engineering Research / Zhongguo Zuzhi Gongcheng Yanjiu is the property of Chinese Journal of Tissue Engineering Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Icariin is an effective active component of traditional Chinese medicine which is used to prevent osteoporosis, but the specific mechanism remains unclear. Existing studies have indicated that autophagy can participate in regulating bone metabolism; however, whether icariin can prevent osteoporosis by changing autophagy is unknown. OBJECTIVE: To investigate whether icariin can prevent osteoporosis by regulating autophagy and promoting osteoblast differentiation. METHODS: Mouse preosteoblast cell lines MC3T3-E1 in logarithmic phase were selected and treated by different concentrations of icariin (10-6 to 10-3 mmol/L). Cell viability, apoptosis rate, alkaline phosphatase activity, the number of mineralized nodules and the expression level of osteogenic differentiation markers were observed in order to determine the optimal concentration of icariin. Then cells were treated by the optimal concentration of icariin and divided into three groups: control group, icariin group, icariin+3-methyladenine group. The number of autophagosomes, the expression level of osteogenic differentiation markers and autophagy related genes, the expression level of autophagy related proteins were evaluated by MDC staining, RTqPCR and western blot assay, respectively. In an in vivo test, an ovariectomized rat model was established and all the rats were divided into four groups: sham group, ovariectomized group, icariin group, estradiol group. Micro-CT was used to detect the bone micro parameters, and western blot was used to detect the expression level of autophagy related proteins. RESULTS AND CONCLUSION: Icariin could promote the proliferation and differentiation of osteoblasts, and at the same time inhibit apoptosis of the cells. The maximum stimulatory effect of icariin was observed at the concentration of 10-5 mmol/L (P < 0.05). In addition, icariin could increase the number of autophagosomes and upregulate the expression of osteogenic differentiation markers and autophagy-related genes or proteins (P < 0.05), which were antagonized by 3-methyladenine (P < 0.05). Icariin could also improve the parameters of bone microstructure in ovariectomized rats and upregulate the expression of autophagy-related proteins (P < 0.05). All these findings indicate that icariin can prevent osteoporosis by activating autophagy and promoting osteoblast differentiation. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is an effective strategy for the treatment of osteoporosis to promote the proliferation and differentiation of osteoblasts, but the influence of inokosterone onosteoblast proliferation and differentiation is rarely reported.OBJECTIVE: To investigate the effects of inokosterone on theproliferation and differentiation of primary osteoblasts and the underlying molecular mechanism.METHODS:Primary osteoblasts from neonatal Sprague-Dawley rats were isolated via the second enzyme digestion, and the cells were then cultured in osteogenic induction medium and identified. Cell counting kit 8 assay was performed to evaluate the effect of different concentrations of inokosterone (1, 5, 10 mg/L) on cell viability of primary osteoblasts. Early differentiation ability of osteoblasts was evaluated by alkaline phosphatase staining and alkaline phosphatase activity assay. To evaluate the mineralization ability of osteoblasts, alizarin red staining was performed to observe the number of calcium nodules. The expression level of osteogenic genes was detected by RT-qPCR at different time points. Furthermore, MDC staining was also used to observe the number of autophagosomes. RESULTS AND CONCLUSION: Compared with the control group, inokosterone could inhibit the cell viability of primary osteoblast to some degree (P < 0.05) while significantly promoting alkaline phosphatase activity and mineralized nodules formation (P< 0.05). In addition, inokosterone upregulated the expression of osteogenic genessuch as Collagen I, osteoprotegerin, osteopontin, osteocalcin and increased the number of autophagosomes. To conclude, inokosterone can promote osteogenic differentiation by upregulating osteogenic genes expression and activating autophagy of primary osteoblasts. [ABSTRACT FROM AUTHOR]