Anti-inflammatory and biocompatibility effects of Portulaca oleracea and nanoparticles on the bone

Abstract

Background: Bone healing depends on a well-balanced and highly coordinated process of inflammation, repair, and bone remodeling. Portulaca oleracea and gold nanoparticles (Au-NPs) have demonstrated potential applications in wound healing in soft tissues; however, their potential in hard-tissue bone regeneration has yet to be studied in comparison with each other and within the context of biocompatibility.
Objective: to assess and compare the anti-inflammatory and biocompatibility effects of Portulaca oleracea extract and Au-NPs on early bone healing in a standardized defect model of tibia of the rabbit.
Materials and Methods: Cortical bone defects were surgically created in the tibiae of rabbits and assigned to three independent groups: topical Portulaca oleracea extract treatment, Au-NP treatment, and untreated control. Histological and histomorphometric assessments were conducted at critical early time points (days 3 and 7 post-surgery) to determine the inflammatory cell dynamics, proliferation of fibroblasts, osteoblast and osteocyte activity, and neovascularization.
Results: Morphometric analysis of the bone defect area showed that the application of Portulaca oleracea extract and gold nanoparticles (Au-NPs) had a significant effect on the process of tissue healing and osteogenesis. All experimental groups had a significant decrease in the number of inflammatory cells and a significant increase in blood vessel density and in the number of fibroblasts by day 7, when compared with the control group. Importantly, the treatment with Portulaca oleracea achieved the highest vascularization at day 3, and reduced inflammation significantly at day 7. In addition, both interventions resulted in early recruitment of osteoblasts at day 3 and Au-NP treatment resulted in the highest osteocyte density at day 7.
Conclusion: Results suggest that the bone defect repair process is promoted by the extract of Portulaca oleracea and Au-NPs in independent but synergic cellular mechanisms during early stages. Both Au-NPs and Portulaca oleracea are highly biocompatible and are potential therapeutic agents for bone tissue regeneration.