Total Flavonoids of Rhizoma Drynariae Enhances Angiogenic-Osteogenic Coupling During Distraction Osteogenesis by Promoting Type H Vessel Formation Through PDGF-BB/PDGFR-β Instead of HIF-1α/ VEGF Axis

Abstract

Background: Total flavonoids of Rhizoma Drynariae (TFRD), extracted from the kidney-tonifying traditional Chinese medicine Rhizoma Rrynariae, has been proved to be effective in treating osteoporosis, bone fractures and defects. However, pharmacological effects of TFRD on type H vessels, angiogenic-osteogenic coupling in distraction osteogenesis (DO) and the mechanism remain unclear. This study aims at investigating whether type H vessels exist in the DO model, effects of TFRD on angiogenic-osteogenic coupling and further elucidating the underlying mechanism.Methods: Rats models of DO and bone fracture (FR) were established, and then were separately divided into TFRD and control subgroups. Imageological and histological analyses were performed to assess bone and vessel formation. Immunofluorescent staining of CD31 and endomucin (Emcn) was conducted to determine type H vessel formation. Matrigel tube formation, ALP and Alizarin Red S staining assays were performed to test the effects of TFRD on angiogenesis or osteogenesis of endothelial precursor cells (EPCs) or bone marrow-derived mesenchymal stem cells (BMSCs). Additionally, expression levels of HIF-1α, VEGF, PDGF-BB, RUNX2 and OSX were determined by ELISA, qPCR or western blot, respectively.Results: The in vivo results indicated more formed type H vessels in DO groups than in FR groups and TFRD obviously increased the abundance of type H vessels. Moreover, groups with higher abundance of type H vessels showed better angiogenesis and osteogenesis outcomes. Further in vitro experiments showed that TFRD significantly promoted while blocking PDGF-BB remarkably suppressed the angiogenic activity of EPCs under stress conditions. The levels of p-AKT and p-ERK1/2, downstream mediators of the PDGF-BB pathway, were up-regulated by TFRD but blocked by function blocking anti-PDGF-BB antibody. In contrast, the activated AKT and ERK1/2 and corresponding tube formation were not affected by the HIF-1α inhibitor. Besides, blocking PDGF-BB inhibited the osteogenic differentiation of the stretched BMSCs, but TFRD enhanced the osteogenic activity of BMSCs and ameliorated the inhibition, with more calcium nodes, higher ALP activity and mRNA and protein levels of RUNX2 and OSX.Conclusion: Type H vessels exist in the DO model and TFRD enhances angiogenic-osteogenic coupling during DO by promoting type H vessel formation via PDGF-BB/PDGFR-β instead of HIF-1α/VEGF axis.

Total Flavonoids of Rhizoma Drynariae Promotes Differentiation of Osteoblasts and Growth of Bone Graft in Induced Membrane Partly by Activating Wnt/β-Catenin Signaling Pathway

“…In the range of dose and time of our study, TFRD was relatively safe for non-cancer rats. According to the current reports, after TFRD acted on the rat models of bone defect, fracture, osteoporosis and osteonecrosis of femoral head, no carcinogenic and other adverse reactions were found (Song et al, 2016;Song et al, 2017;Yao et al, 2018;Guo et al, 2019;Shen et al, 2020;Lv et al, 2021). The doses of administration in these articles can be summarized as 75-440 mg/kg/d (oral administration) and 20 mg/kg/day (intraperitoneal injection), respectively.…”

Identifying a possible new target for diagnosis and treatment of postmenopausal osteoporosis through bioinformatics and clinical sample analysis

“…Studies have shown that when E2 binds to ERα, SRC forms the complex, SHP2-c-Src, in a non-genomic manner which weakens RANKL stimulation-induced c-Src activation, resulting in impaired actin ring formation and reduced bone reabsorption (27). At the same time, Src was also considered as one of the important protein targets of Rhizoma Drynariae in a network pharmacological study of Rhizoma Drynariae, a traditional Chinese medicine with anti-inflammatory and anti-oxidative effects on bone (28)(29)(30)(31). To conclude, through combining bioinformatic analysis with gene expression and microarray analysis, our study has discovered the abnormal expression of genes and pathways in patients of postmenopausal osteoporosis.…”

Rhizoma Drynariae promotes the Osteogenic differentiation of Bone Mesenchymal Stem Cells by activating the Wnt/β-catenin Signaling Pathway

“…Research has shown that RD could enhance angiogenic-osteogenic coupling during distraction osteogenesis by promoting type H vessel formation through PDGF-BB/PDGFR-β signaling pathway 14 . RD could promote osteoblast differentiation and mineralization in MC3T3-E1 cells through regulation of bone morphogenetic protein-2, alkaline phosphatase, type I collagen and collagenase-1 29 .…”

“…Rhizoma Drynariae (RD), the dried rhizome of Drynaria fortune (Kunze) J. Sm., has been widespread and been proved to be effective in treating OP, bone fractures and defects [11][12][13][14][15][16] . Due to the minimum side effects and favorable cost-effective therapeutic effects, RD has been widely used in clinical practices for more than 2,100 years in China.…”

“…RD has been proved to exert multifaceted pharmacological effects on the bone homeostasis, such as up-regulating the expression levels of BMP-2 and Runx2 18, 19 , promoting osteoblast proliferation and differentiation 20,21 , inhibiting osteoclast activity and preventing bone loss 17,22,23 . In recent years, there have been a lot of reports on RD's anti-osteoporosis treatment 14,17,23 , but the mechanism of its anti-osteoporosis action from the perspective of Wnt/β-catenin signaling pathway is still very few.…”