Accelerated healing by composites containing herb epimedium for osteoinductive regeneration

Explorating the mechanism of Epimedii folium-Rhizoma drynariae herbal pair promoted bone defects healing through network pharmacology and experimental studies

ETHNOPHARMACOLOGICAL RELEVANCE

Bone defects are difficult to treat and have a high incidence of nonunion. The Epimedii folium-Rhizoma drynariae herbal pair (EDP) is a traditional Chinese medicine (TCM) used for treating bone diseases. However, the mechanisms by which EDP promotes osteogenesis or bone formation remain largely unclear.

AIM OF THE STUDY

This study aimed to investigate the mechanism of EDP promoted bone formation in bone defects using network pharmacology and experiments.

MATERIALS AND METHODS

The chemical components of EDP were analyzed by UHPLC-MS. The hub target and pathway enrichment analysis was conducted using molecular docking or network pharmacology. The pharmacological actions of EDP were determined by μCT and histopathology examination using a bone defect rat model. The effects of EDP on the mRNA expression of Bmp2, Smad2/5, Runx2, and Alp genes were measured by RT-PCR, while changes in the protein expressions of BMP2, COL1A1, SPP1, ALP, and RUNX2in the tibia tissues of the rats in response to EDP were analyzed by immunohistochemical staining or Western blot. We also performed cell viability assays, Alizarin Red and ALP staining assays, and RT-PCR to better understand how EDP affected osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).

RESULTS

Identified 14 key compounds and 47 hub targets of EDP that may be involved in promoting osteogenesis to repair bone defects. And the BMP/Smad/Runx2 pathway was likely the key pathway through which EDP promoted bone defects repairing. The results of in vivo rat experiments indicated that EDP effectively promoted tibia repair in the model rats and activated the BMP/Smad/Runx2 pathway in the tibia tissue, with upregulating Bmp2, Bmpr1α, Smad2/5, Runx2, and Alp genes, and increased the protein expression of BMP2, COL1A1, RUNX2, and ALP. In vitro, EDP was found to increase the proliferation, differentiation, and mineralization in BMSCs- and also up-regulated the expression of key genes in the BMP/Smad/Runx2 pathway.

CONCLUSION

This study highlighted the ability of EDP to promote the osteogenic differentiation to enable bone repair by activating the BMP/Smad/Runx2 pathway.

PLGA scaffold carrying icariin to inhibit the progression of osteoarthritis in rabbits

Icariin, the main effective component extracted from epimedium, has been shown to stimulate osteogenic differentiation and bone formation and to increase synthesis of the cartilage extracellular matrix. However, there has been little study on the effects of icariin on osteoarthritis. In this study, we loaded icariin onto poly(lactic-co-glycolic acid) (PLGA) electrospinning. The aim of this study was to explore a composite scaffold and to inhibit the progression of osteoarthritis. Our main experimental results demonstrated that the PLGA/icariin composite spinning scaffold had higher hydrophilicity, and icariin was released slowly and steadily from the scaffold. According to the results of an MTT test, immunofluorescence staining, an alkaline phosphate activating assay and a real-time polymerase chain reaction (RT-PCR) assay, the PLGA/icariin composite scaffold had good biocompatibility. In models of osteoarthritis, the results of a RT-PCR assay indicated that the PLGA/icariin scaffold promoted the synthesis of the extracellular matrix. The results of X-ray microtomography and histological evaluation demonstrated that the PLGA/icariin scaffold maintained the functional morphology of articular cartilage and inhibited the resorption of subchondral bone trabeculae. These findings indicated that the PLGA and icariin composite scaffold has therapeutic potential for use in the treatment of osteoarthritis.