Atractylodes Macrocephala Koidz. Derived Exosome-Like Nanovesicles Promoted Osteogenic Differentiation of hBMSCs Via Regulating SOD2 and Postponed Osteoporosis of Ovariectomized Rats

Objective: Osteoporosis is a chronic disease associated with decreased bone strength and a heightened susceptibility to fractures. Atractylodes macrocephala Koidz. (AMK) is a traditional Chinese herb that tonifies the spleen and invigorates qi, which helps to strengthen muscles and bones. In this study, AMK-derived exosome-like nanovesicles (AMKELNs) are studied to determine whether they function in osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) and in osteoporosis of ovariectomized (OVX) rats. Methods: AMKELNs were extracted from the rhizome of AMK by differential centrifugation, whose structure was visualized by transmission electron microscopy, and the particle size was determined by nanoparticle tracking analysis. A series of experiments, such as quantitative reverse transcription polymerase chain reaction (qRT-PCR), western blot, alkaline phosphatase (ALP) activity, and alizarin red staining, were conducted to evaluate the effect of AMKELNs on osteogenic differentiation of hBMSCs. Furthermore, AMKELNs were intraperitoneally injected into OVX rats for 12 weeks of treatment. Micro computed tomography (Micro-CT) and histological staining were performed to assess the effects of AMKELNs on osteoporosis. Results: AMKELNs with an intact bilayer membrane and an average size of 141.9 ± 0.5 nm were successfully internalized by hBMSCs and absorbed by Sprague-Dawley rats. Moreover, AMKELNs stimulated the osteogenic differentiation of hBMSCs by up-regulating the expression of superoxide dismutase 2 (SOD2). In the animal experiment (n = 5), AMKELNs could effectively preserve the bone mass of rats and improve the bone parameters. Conclusions: Our results indicate that AMKELNs represent a promising therapeutic method for osteoporosis. This study proposes a new theoretical perspective on bone tissue repair strategies based on a natural drug nano-delivery system.