Effect of freeze dried bovine amniotic membrane extract on full thickness wound healing

This study explored the feasibility of development of solubilized amniotic membrane extract (AME) as a potential wound healing substrate with improved efficacy. Bovine amniotic membrane was extracted using a mixture of acetic acid and 2-mercaptopropionic acid under sonication, which was followed by the frozen, and then lyophilized processes. The effects of AME on cell migration and growth properties were evaluated from 0 to 24 h of post injury using primary human foreskin fibroblast monolayer culture with one line scratch as an in vitro wound model. Its wound healing efficacy and scar preventive effects were investigated using whole thickness biopsy punch (8 mm) wound model obtained from rabbit ear. Intra dermal injections of AME fluid (10 μl of 1.2 μg/μl) on four wound sites were performed at 1 h pre injury, post 1, 2 and 3 day. The processes and levels of re-epithelialization and dermal regeneration were examined through histological assessment with H-E staining. In cell migration study conducted at 24 h post injury, AME (1.7 μg/ml) treated cells significantly increased wound closure with 54.9 % compared to control. Histological image analysis on AME treated wound sites at 36 days post injury showed properly developed epidermal basal cell layers and weave-like dermal collagen bundles, whereas those of untreated control skin showed over-proliferation of epidermis and aggregated collagen bundles with defected dermal regeneration. The results of this study verified the feasibility of dermal injections of freeze dried AME as a potential wound healing substrate which can promote epidermal and dermal regeneration, while avoiding undesirable hyper-proliferation of damaged tissue.