The anti-inflammatory effect of PHBV/Collagen (PHCP) was examined in a mouse model of lipopolysaccharide (LPS)-induced skin inflammation. Vascular permeability on the back skin was measured by the local accumulation of Evan’s blue dye after subcutaneous injection of LPS (30 µg site^-1 ). Dye leakage in the skin showed a significant increase at 2 h after injection of LPS. This LPS-induced dye leakage was also completely inhibited by HO-1 inhibitor, ZnPP, and antioxidants, including methyl gallate, trolox, and mannitol. To study the possible mechanisms underlying the in vivo anti-inflammatory effect of PHCP against LPS-induced inflammation, we also examined the effects of PHCP on malondialdehyde (MDA) and glutathione levels in skin tissues and found that pretreatment with PHCP resulted in inhibited MDA elevation and a remarkable reduction of glutathione level. In addition, similar results were obtained after pretreatment with antioxidants, including trolox and mannitol, and HO-1 inhibitor, ZnPP. Histopathologically, an influx of neutrophils into the skin dermis was detected between 24 h and 72 h after LPS injection (30, 100 µg site^-1), compared to control animals after injection of saline. This increase was greater in mice treated with 100 µg of LPS than in those treated with 30 µg of LPS and was significantly suppressed by pretreatment with PHCP, antioxidants, and HO-1 inhibitor. These results collectively suggest that PHCP has an anti-inflammatory effect against LPS-induced inflammation model in vivo and may be a good candidate for the skin tissue engineering biomedical application primarily through manipulation of the redox state.

In this study, a nanofibrous scaffold was obtained by co-electrospinning poly (3-hydroxybutyrate- co-3-hydroxyvalerate) (PHBV) and collagen in 2,2,2-trifluoroethanol at a ratio of 3/7. The fiber diameters were in the range of 250-600 nm. It was found that PHBV/Collagen (PHCP) nanofibrous scaffold showed greater proliferation than the PHBV nanofibrous scaffold induced by oxidant in NIH3T3 cells. Otherwise, in the early-stage wound-healing mouse model, wound closure was evaluated according to wound size reduction and histology of regenerated skin on the backs of mice. Each of the tissues removed on day 0, 3, 6, 9, 12, 15, and 18 was used for analysis of biochemical and pathological changes. None of the nanofiber-attached mice showed significant difference on the third day, however, from the third day until the ninth day, significantly faster healing was observed in PHCP-attached mice, compared to control wounds in epithelialization, wound contraction, and histopathological examinations. These results strongly support the beneficial effects of biomedical application of PHCP nanofiber in acceleration of the initial phase of wound healing through α-SM actin contraction.