Effect of Different Collection Times of Dermal Fibroblast Conditioned Medium (DFCM) on In Vitro Re-Epithelialisation Process

A key event in wound healing is re-epithelialisation, which is mainly regulated via paracrine signalling of cytokines, chemokines, and growth factors secreted by fibroblasts. Fibroblast-secreted factors can be collected from the used culture medium, known as dermal fibroblast conditioned medium (DFCM). The goal of this study was to optimise the culture condition to acquire DFCM and evaluate its effect on keratinocyte attachment, proliferation, migration, and differentiation. Confluent fibroblasts were cultured with serum-free keratinocyte-specific (DFCM-KM) and fibroblast-specific (DFCM-FM) medium at different incubation times (Days 1, 2, and 3). DFCM collected after 3 days of incubation (DFCM-KM-3 and DFCM-FM-3) contained a higher protein concentration compared to other days. Supplementation of DFCM-KM-3 enhanced keratinocyte attachment, while DFCM-FM-3 significantly increased the keratinocyte wound-healing rate, with an increment of keratinocyte area and collective cell migration, which was distinctly different from DFCM-KM-3 or control medium. Further analysis confirmed that the presence of calcium at higher concentrations in DFCM-FM facilitated the changes. The confluent dermal fibroblasts after 3 days of incubation with serum-free culture medium produced higher proteins in DFCM, resulting in enhanced in vitro re-epithelialisation. These results suggest that the delivery of DFCM could be a potential treatment strategy for wound healing.