Adipose stem cell-laden injectable thermosensitive hydrogel reconstructing depressed defects in rats: filler and scaffold

Abstract

H NMR showed the successful synthesis of the crosslinker. In vitro tests, CCK-8 assay and live/dead viability test showed that the hydrogel was non-toxic to adipose-derived stem cells (ASCs). SEM images also confirmed that ASCs could adhere to the hydrogel. Then we constructed a novel depressed defect model in rats and injected four different fillers in the depressed defects: (1) the hydrogel with ASCs, (2) the hydrogel only, (3) hyaluronic acid, and (4) PBS. After 4 weeks, gross and histological analyses showed the defects in hydrogel, hydrogel + ASCs, and HA groups improved significantly and there were no significant differences among them. Significant differences in thickness from skin to muscle in the defect was found between the hydrogel + ASCs group and the other groups after 6 months. The hydrogels degraded completely in defects in both the hydrogel group and the hydrogel + ASCs group, and were filled with adipocytes and multilocular immature adipocytes. Immunohistochemical study using s-100 and perilipin staining revealed adipocyte differentiation in the defect sites. We also used green fluorescent protein (GFP)-ASCs for tracing and found that exogenous added ASCs were involved in adipogenesis. In conclusion, such a cell attachable thermosensitive hydrogel has definite potential not only as a filler but also as a scaffold, and has a persistent effect for small depressed defects. It might ultimately become a new material in plastic and reconstructive surgery.