从海马-HPO轴探讨龟板调控let-7f抗老年性骨质疏松症的神经内分泌机制

Previous experiments confirmed that let-7f played an important role in bone homeostasis and hippocampal-HPO axis. Hippocampus, as a high-level regulation center of the HPO axis, plays an important role in bone homeostasis by negative feedback in regulation of HPO axis to release estrogen, which is highly similar to kidney-brain correlation theory "the kidney dominating the bones and marrow; bone filled with marrow, which converges in the brain" of Chinese medicine. Thus, studying the neuroendocrine mechanism of let-7f-mediated hippocampal-HPO axis in regulation of bone homeostasis is a new direction for Chinese medicine to prevent and treat senile osteoporosis (SOP). The plastrum testudinis has the effect of strengthening the kidney and bone, filling the essence and marrow in Chinese medicine. We also confirmed that it could effectively improve the bone damage of SOP. Therefore, we hypothesize that plastrum testudinis regulates the hippocampus-HPO axis anti-SOP through let-7f. To verify the hypothesis, some techniques such as conditional let-7f knockout in bone marrow/hippocampus, qPCR, WB and ELISA, will be employed in two main experiments from different levels, one is to explore the role of let-7f in regulation of hippocampus-HPO axis in plastrum testudinis anti-SOP in vivo, and one is to investigate the effect of let-7f on hippocampus-HPO axis in regulation of osteoblast and osteoclast differentiation and the intervention mechanism of plastrum testudinis in vitro. This study may provide an experimental basis for clarifying the neuroendocrine mechanism of SOP and enriching the scientific connotation of the "homogeny of kidney-brain " theory.

前期实验证实let-7f在骨稳态、海马-HPO轴中均扮演着重要调控角色。海马作为HPO轴的高级调节中枢，通过负反馈调控HPO轴释放雌激素在骨稳态中发挥重要作用，与中医学“肾主骨生髓，髓充于骨，汇于脑”的肾脑理论高度相似，研究let-7f介导海马-HPO轴调控骨稳态的神经内分泌机制是中医药防治老年性骨质疏松症（SOP）的新方向。龟板具有补肾强骨、填精益髓的功效，我们前期也证实其能有效改善SOP骨损害。因此，我们提出“龟板通过let-7f调控海马-HPO轴抗SOP”的假说。本研究拟用骨髓/海马let-7f 条件性基因敲除、qPCR、WB、ELISA等技术从不同层面进行研究：①体内探讨let-7f调控海马-HPO轴在龟板抗SOP中的作用；②体外探讨let-7f调控海马-HPO轴对成、破骨分化的作用及龟板的干预机制。这为明确SOP神经内分泌机制及丰富“肾脑同源”理论的科学内涵提供实验依据。

Let-7f在骨稳态、海马-HPO轴中均扮演着重要调控角色。海马通过负反馈调控HPO轴在骨稳态中发挥重要作用。龟板补肾强骨、填精益髓，能有效改善骨丢失。因此，我们从海马-HPO轴探讨龟板调控Let-7f抗老年性骨质疏松症（SOP）的神经内分泌机制。主要研究如下：①完成龟板干预SOP（包括快速衰老及自然衰老）小鼠实验，表明龟板可以改善SOP小鼠骨量和海马区细胞衰老情况。同时，龟板上调了海马和骨组织Let-7f的表达。②完成骨髓和海马Let-7f条件性敲除（简称Let-7f海马CKO和骨髓CKO）实验，表明Let-7f海马CKO小鼠呈现海马衰老和骨损害特征；Let-7f骨髓CKO小鼠呈现骨量损害；在Let-7f海马CKO和骨髓CKO小鼠上构建SOP模型，亦表现骨量损害特征。同时，Let-7f海马和骨髓CKO小鼠呈现海马-HPO轴的失衡。这为明确SOP神经内分泌机制及丰富“肾脑同源”理论的科学内涵提供实验依据。