Development and functional testing of a novel in vitro delayed scratch closure assay

Area of Science:

• Biomedical Engineering
• Wound Healing Research
• Cell Biology

Background:

• Current in vitro models often mimic acute wounds, not the complex inflammatory microenvironment of chronic wounds.
• Chronic wound healing is hindered by persistent trauma and pro-inflammatory signaling, particularly in conditions like diabetes.
• Advanced assay systems are needed to better replicate in vivo chronic wound conditions.

Purpose of the Study:

• To develop and characterize a novel in vitro delayed scratch closure model simulating chronic wound features.
• To assess the efficacy of a mesenchymal stem cell (MSC) secretome on delayed wound healing in this new model.
• To provide a more relevant preclinical tool for evaluating chronic wound therapeutics.

Main Methods:

• A delayed scratch closure model was created by inducing physical scratches and stimulating with pro-inflammatory factors (interferon, PMA, lipopolysaccharide).
• Concentrations of these factors were optimized for human keratinocyte (HaCaT) and dermal fibroblast (HDF) cell lines.
• The model's responsiveness was tested using a proprietary healing secretome from human Wharton's jelly MSCs.

Main Results:

• The established model successfully mimicked delayed scratch closure characteristic of chronic wounds.
• Human keratinocyte (HaCaT) cells in the delayed closure model responded positively to the MSC secretome treatment.
• The MSC secretome demonstrated efficacy in promoting closure of previously non-healing scratches.

Conclusions:

• The developed delayed scratch closure model offers a valuable in vitro system for studying chronic wound pathophysiology.
• This model can be utilized by researchers to screen and validate the effectiveness of novel drugs and biological treatments for chronic wounds.
• It serves as a crucial step before progression to more complex preclinical testing, such as explanted tissues or in vivo studies.