RESUMO
Tissue engineering combines cells, scaffolds and signalling molecules to synthesize tissues in vitro. However, the lack of a functioning vascular network severely limits the effective size of a tissue-engineered construct. In this work, we have assessed the potential of reduced graphene oxide (rGO), a non-protein pro-angiogenic moiety, for enhancing angiogenesis in tissue engineering applications. Polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) scaffolds loaded with different concentrations of rGO nanoparticles were synthesized via lyophilization. Characterization of these scaffolds showed that the rGO-loaded scaffolds retained the thermal and physical properties (swelling, porosity and in vitro biodegradation) of pure PVA/CMC scaffolds. In vitro cytotoxicity studies, using three different cell lines, confirmed that the scaffolds are biocompatible. The scaffolds containing 0.005 and 0.0075% rGO enhanced the proliferation of endothelial cells (EA.hy926) in vitro. In vivo studies using the chick chorioallantoic membrane model showed that the presence of rGO in the PVA/CMC scaffolds significantly enhanced angiogenesis and arteriogenesis.
RESUMO
BACKGROUND: Wound healing occurs as a fundamental response to tissue injury. Several natural products have been shown to accelerate the healing process. AIM: To observe the efficacy of topical administration of an ethanolic extract of Ageratum conyzoides on cutaneous wound healing in rats. METHODS: An ethanolic extract of A. conyzoides was prepared, and its wound-healing efficacy on rats was studied. An open excision wound was made on the back of each rat, and 200 µL (40 mg/kg body weight) of the A. conyzoides extract was applied topically once daily to the treated wounds. The control wounds were treated with 200 µL of 50% ethanol. The wound tissues formed were removed at 4, 8 and 12 days after wounding, and biochemical parameters such as DNA, total protein, total collagen, hexosamine and uronic acid were estimated. The extent of epithelialization and the tensile strength of the wounded tissues were also measured. RESULTS: The A. conyzoides extract increased cellular proliferation and collagen synthesis. Wounds treated with the extract were found to heal much faster, based on the improved rates of epithelialization and wound contraction, and on the histopathological results. A 40% increase in the tensile strength of the treated tissue was seen. CONCLUSIONS: Topical application of A. conyzoides accelerates the rate of wound healing.
