The enhanced permeability and retention effect based nanomedicine at the site of injury

The enhanced permeability retention(EPR)effect based nanomedicine has been widely used for tumor targeting during the past decades.Here we unexpectedly observed the similar"EPR effect"at the site of iniury.We found that the temporary dilated and leaky blood vessels caused by the potent vasodilator histamine in response to injury allowed the injected nanoparticles to pass through the vasculature and reached the injured tissue.Our finding shows the potential underline mechanism of"EPR effect"at the injured site.By loading with antibiotics,we further demonstrated a new strategy for prevention of infection at the site of injury.

Extracts of Portulaca oleracea promote wound healing by enhancing angiology regeneration and inhibiting iron accumulation in mice

Objective:To investigate the role of Portulaca oleracea(POL)in promoting revascularization and reepithelization as well as inhibiting iron aggregation and inflammation of deep tissue pressure injury(DTPI).Methods:The hydroalcoholic extract of POL(P)and aqueous phase fraction of POL(PD)were prepared based on maceration and liquid–liquid extraction.The number of new blood vessels and VEGF-A expression level were assessed using H&E stain and Western blot on injured muscle to examine the role of POL different extracts in vascularization.The iron distribution and total elemental iron of injured muscle were detected using laser ablation inductively coupled plasma mass spectrometry(ICP-MS)and Perls’staining to determine whether POL extracts can inhibit the iron accumulation.Besides,the ability of POL extracts to promote wound healing by combining re-epithelization time,inflammation degree and collagen deposition area were comprehensively evaluated.Results:In vitro,we observed a significant increase in HUVEC cell viability,migration rate and the number of the tube after P and PD treatment(P<0.05).In vivo,administration of P and PD impacted vascularization and iron accumulation on injured tissue,evident from more new blood vessels,higher expression of VEGF-A and decreased muscle iron concentration of treatment groups compared with no-treatment groups(P<0.05).Besides,shorter re-epithelization time,reduced inflammatory infiltration and distinct collagen deposition were associated with administration of P and PD(P<0.05).Conclusion:POL extract administration groups have high-quality wound healing,which is associated with increased new blood vessels,collagen deposition and re-epithelization,along with decreased iron accumulation and inflammatory infiltration.Our results suggest that that POL extract is beneficial to repair injured muscle after ischemia–reperfusion,highlighting the potential of POL in the DTPI treatment.