Efficacy of total flavonoids of Rhizoma drynariae on the blood vessels and the bone graft in the induced membrane

The sustained-release agent of total flavonoids of Rhizoma drynariae prepared by nano-mesoporous silica can still promote osteogenesis and angiogenesis in vitro

Total flavonoids of Rhizoma drynariae (TFRD) possess the ability to enhance bone formation by promoting the coupling of angiogenesis and osteogenesis. However, the limited duration of serum concentration necessitates frequent oral administration. Designing TFRD as a sustained-release agent could enhance patient's compliance and extend efficacy. Mesoporous silica nanoparticles (MSNPs) were used as a carrier for the preparation of a sustained-release agent containing TFRD (TFRD@MSNPs). Material characterization confirmed the successful loading of TFRD onto MSNPs. Subsequently, HUVECs were treated with varying concentrations of TFRD or TFRD@MSNPs to evaluate their effects on proliferation and migration ability. The secretion levels of VEGF, VCAM-1, EGF, TGF-β1, and type H endothelial markers (CD31 and EMCN) were assessed. BMSCs were cultured in conditioned medium derived from HUVECs induced by either TFRD or TFRD@MSNPs to evaluate their osteogenic potential in vitro. Gene expressions of ALP, OCN, and RUNX2, alkaline phosphatase activity, and calcium deposition were measured. The mass fraction of TFRD in the sustained release system TFRD@MSNP was approximately 60%. An appropriate concentration (< 400 µg/mL) of TFRD promoted the proliferation and migration of HUVECs, inhibited the secretion of TGF-β1, and increased the expression levels of VEGF, VCAM-1, EGF, CD31, and EMCN. The conditioned medium from HUVECs induced by TFRD significantly enhanced the osteogenic differentiation potential of BMSCs. An appropriate concentration of TFRD@MSNPs promoted the proliferation and migration of HUVECs, as well as the expression levels of CD31 and EMCN, but had no significant effect on VEGF, VCAM-1, EGF, or TGF-β1 secretion. The conditioned medium from HUVECs induced by TFRD@MSNPs increased ALP, OCN, and RUNX2 gene expression in BMSCs to varying degrees. Compared to the conditioned medium induced by TFRD in HUVECs, the conditioned medium induced by TFRD@MSNPs resulted in more calcium deposits in BMSCs. The sustained-release agent TFRD prepared by MSNPs can effectively promote the osteogenic differentiation of BMSCs through the coupling effect of angiogenesis and osteogenesis in vitro. These findings suggest that using MSNPs to formulate TFRD as sustained-release agent holds potential for clinical application, but the specific mechanism remains to be elucidated.

Effects of a functional milk powder supplemented with rhizoma drynariae extracts on bone health in growing and ovariectomized rats: More effective for lumbar vertebrae?

Bone health is vital through all life stages and has become a growing public health concern. The role of rhizoma drynariae (RD) as a traditional Chinese medicine for bone injury recovery has been widely investigated. Still, there is little research related to RD as a functional component in food to improve calcium bioavailability and bone health. Milk powder is a daily vital food source of dietary calcium. The present study aimed to investigate and compare the effects of a functional milk powder reinforced with RD extracts (RDE) or vitamin D, vitamin K2, and calcium, or both, using Sprague-Dawley rats, with both low calcium growing rat model and low calcium ovariectomized (OVX) rat model. For growing rats, RDE increased bone mineral density (BMD) and improved the microstructure of bone trabecula in the femur and lumbar vertebrae. The levels of serum bone turnover markers CTX-I, PINP, and BGP were increased with RDE supplementation. The tartrate-resistant acid phosphatase staining suggested a decrease in the number of osteoclasts in the femur. Immunohistochemistry showed that the osteoclast-related protein RANKL was downregulated, and the osteogenic-associated proteins RUNX2 and OSX significantly increased in the lumbar vertebrae. Similarly, in OVX rats, RDE improved BMD and microstructure in lumbar vertebrae, and the levels of CTX-I, PINP, and BGP were also increased. In conclusion, the novel functional milk powder supplemented with RDE facilitated osteogenesis and inhibited osteoclast in rats at both stages, especially with lumbar vertebrae in growing rats. Our findings provide new prospects and a more precise target for enhancing bone health by incorporating RDE as a functional component in milk powder.

Active components and mechanisms of total flavonoids from Rhizoma Drynariae in enhancing cranial bone regeneration: An investigation employing serum pharmacochemistry and network pharmacology approaches

ETHNOPHARMACOLOGICAL RELEVANCE

Rhizoma Drynariae, as the dried rhizome of Drynaria fortunei (Kunze ex Mett.) J. Sm., is a traditional Chinese medicine for treating the injury and bone broken of falling and beating. Total flavonoids is considered as the major and effective compounds for the therapeutic efficacy of Rhizoma Drynariae.

AIM OF THE STUDY

To explore the effect of total flavonoids from Rhizoma Drynariae (TFRD) on bone regeneration and the underlying mechanisms.

MATERIALS AND METHODS

The effect of TFRD in various doses on bone reconstruction in cranial bone defect rats was explored in vivo. The active ingredients in TFRD-medicated serum were characterized by serum pharmacochemistry and integrated by network pharmacology analysis and target prediction. To elucidate the underlying mechanism of TFRD on bone regeneration, experimental validation in vitro was executed to assess the influence of different concentrations of TFRD-medicated serum on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Micro-CT, histological examination, immunohistochemical analysis, and ELSA demonstrated that administration of TFRD could promote bone reconstruction in a rat cranial defect model. We identified 27 active components of TFRD using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Results from CCK8, ALP, and Alizarin Red S staining revealed that TFRD-medicated serum notably enhanced BMSCs proliferation and osteogenic differentiation. qRT-PCR and Western blot harvested results consistent with those predicted by network pharmacology, providing further evidence that TFRD activated the TGF-β signaling pathway to benefit bone regeneration.

CONCLUSION

The active components of TFRD modulate the TGF-β signaling pathway to facilitate osteogenesis, thereby repairing cranial bone defects.

Rutin Gel with Bone Graft Accelerates Bone Formation in a Rabbit Model by Inhibiting MMPs and Enhancing Collagen Activities

Bone graft techniques are used to compensate for bone loss in areas with deficient regeneration. However, matrix metalloproteases (MMPs) can limit bone formation by degrading extracellular matrices, which are required for bone regrowth. Noteworthily, rutin is a natural flavonoid compound that inhibits the genetic expression of various MMPs. Therefore, rutin may serve as an inexpensive and stable alternative to the growth factors used to accelerate dental bone graft healing. This study aimed to evaluate the potential of mixing rutin gel with allograft bone to accelerate the healing of bone defects in an in vivo rabbit model. Bone defects were surgically induced in New Zealand rabbits (n = 3 per group) and subsequently treated with bone grafts along with rutin or control gel. Overall, treatment with rutin significantly prevented the expression of several MMPs and increased type III collagen in the gingiva around the surgical site. Additionally, rutin-treated animals showed enhanced bone formation with higher bone marrow content in the jawbone defect area compared with the control group. Taken together, these findings demonstrate that rutin gel, when added to bone grafts, quickly enhances bone formation and may serve as a suitable alternative to expensive growth factors for the same purpose.

Poly(β-amino ester) Dual-Drug-Loaded Hydrogels with Antibacterial and Osteogenic Properties for Bone Repair

In this study, we developed a poly(β-amino ester) (PBAE) hydrogel for the double release of vancomycin (VAN) and total flavonoids of Rhizoma Drynariae (TFRD). VAN was covalently bonded to PBAE polymer chains and was released to enhance the antimicrobial effect first. TFRD chitosan (CS) microspheres were physically dispersed in the scaffold, TFRD was released from the microspheres, and osteogenesis was induced subsequently. The scaffold had good porosity (90.12 ± 3.27%), and the cumulative release rate of the two drugs in PBS (pH 7.4) solution exceeded 80%. In vitro antimicrobial assays demonstrated the antibacterial properties of the scaffold against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Besides these, cell viability assays indicated that the scaffold had good biocompatibility. Moreover, alkaline phosphatase and matrix mineralization were expressed more than in the control group. Overall, cell experiments confirmed that the scaffolds have enhanced osteogenic differentiation capabilities. In conclusion, the dual-drug-loaded scaffold with antibacterial and bone regeneration effects is promising in the field of bone repair.