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Bacteria cellulose membranes (BCM) are used for wound dressings, bone grafts, tissue engineering, artificial vessels, and dental implants because of their high tensile strength, crystallinity and water holding ability. In this study, the effects of BCM application for 15 days on healing of burn wounds were investigated based on evaluation of skin regeneration and angiogenesis in burn injury skin of Sprague-Dawley (SD) rats. BCM showed a randomly organized fibrils network, 12.13 MPa tensile strength, 12.53% strain, 17.63% crystallinity, 90.2% gel fraction and 112.14 g × m(2)/h highest water vapor transmission rate (WVTR) although their swelling ratio was enhanced to 350% within 24h. In SD rats with burned skin, the skin severity score was lower in the BCM treated group than the gauze (GZ) group at all time points, while the epidermis and dermis thickness and number of blood vessels was greater in the BCM treated group. Furthermore, a significant decrease in the number of infiltrated mast cells and in vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang-1) expression was observed in the BCM treated group at day 10 and 15. Moreover, a significant high level in collagen expression was observed in the BCM treated group at day 5 compared with GZ treated group, while low level was detected in the same group at day 10 and 15. However, the level of metabolic enzymes representing liver and kidney toxicity in the serum of BCM treated rats was maintained at levels consistent with GZ treated rats. Overall, BCM may accelerate the process of wound healing in burn injury skin of SD rats through regulation of angiogenesis and connective tissue formation as well as not induce any specific toxicity against the liver and kidney., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Rapid healing of dermatological wounds is of vital importance in preventing infection and reducing post-treatment side-effects. Here we report the therapeutic effects of phytochemically stabilized gold nanoparticles (pAuNPs) coated on a hydrocolloid membrane (HCM) for curing cutaneous wounds. Furthermore, the remedial effects of pAuNPs on skin regeneration and angiogenesis were examined using Sprague Dawley® (SD) rats with skin injuries after a pAuNP-deposited hydrocolloid membrane (pAuNP-HCM) had been applied for 15 days. The rate of wound closure was 4 times faster in the pAuNP-HCM-treated group than in the gauze (GZ)- or HCM-treated groups in the first 5 days. Moreover, wound widths in the pAuNP-HCM-treated group were significantly reduced after 5-15 days of treatment following the injury, compared with the other groups. In addition, a significant increase in collagen expression and a decrease in matrix metalloproteinase (MMP)-1 expression and transforming growth factor (TGF-β1) concentration were observed in the pAuNP-HCM-treated group on day 5. Wound tissue applied with the pAuNP-HCM showed enhancement of vascular endothelial growth factor (VEGF), angiopoietin 1 (Ang-1), and angiopoietin 2 (Ang-2) expression. Furthermore, the activity of superoxide dismutases (SODs) was significantly increased in the skin tissue of the pAuNP-HCM-treated group, compared with the GZ- or HCM-treated groups. It is probable that the accelerated process of wound healing in the injured skin of SD rats via pAuNP-HCM results from the synergistic regulation of angiogenesis and connective tissue formation, as well as the stimulation of antioxidant effects.

Cellulose is one of the most widespread biomolecules in nature and has been exploited in various applications including scaffolding, tissue engineering, and tissue formation. To evaluate the biocompatibility of cellulose film manufactured from Styela clava tunics (SCT-CF), these films were implanted in Sprague-Dawley (SD) rats for various lengths of time, after which they were subjected to mechanical and biological analyses. The cellulose powders (12-268 m) obtained from SCT was converted into films via casting methods without adding any additives. SCT-CF contained about 98 % α-cellulose and very low concentrations of ββ-cellulose. Additionally, the crystallinity index (CrI) of SCT-CF was lower (10.71 %) than that of wood pulp-cellulose films (WP-CF) (33.78 %). After implantation for 90 days, the weight loss and formation of surface corrugations were greater in SCT-CF than that of WP-CF, while the surface roughness was significantly higher in WP-CF than SCT-CF. However, there were no differences in the number of white blood cells between SCT-CF implanted rats and vehicle implanted rats. The level of metabolic enzymes representing liver and kidney toxicity in the serum of SCT-CF implanted rats was maintained at levels consistent with vehicle implanted rats. Moreover, no significant alteration of the epidermal hyperplasia, inflammatory cell infiltration, redness, and edema were observed in SD rats implanted with SCT-CF. Taken together, these results indicate that SCT-CF showed good degradability and non-toxicity without inducing an immune response in SD rats. Further, the data presented here constitute strong evidence that SCT-CF has the potential for use as a powerful biomaterial for medical applications including stitching fiber, wound dressing, scaffolding, absorbable hemostats and hemodialysis membrane.