Generating an Excisional Skin Wound in a Mouse Model via Punch Biopsy

To create an excisional skin wound, begin by placing an anesthetized mouse in a prone position and shaving its back to expose the epidermis, the outermost skin layer.

Apply a disinfectant solution to reduce the contamination risk. Take a punch biopsy tool — a hollow metal tool with a circular blade at the edge, to create a precise cut.

Position the punch biopsy tool perpendicularly at the center of the pre-prepared surgical area. Apply downward pressure on the epidermis to create a circular incision.

Twist the punch biopsy tool while penetrating the epidermis and dermis — the middle layer of the skin. This generates a complete circular cut on the epidermis and dermis without damaging the underlying fascia which is a fibrous connective tissue layer encasing the muscle.

Dissect the layers of skin following a circular pattern and remove them, creating an excisional skin wound with an exposed subcutaneous layer, ready for immunological studies.

For excisional skin wounding of the recipient animals, confirm a lack of response to toe pinch before shaving a 1- by 2-inch section on the back of the mouse. Gently wipe to remove any stray hairs, and disinfect the exposed skin with sequential 10% povidone-iodine and 70% ethanol-soaked gauze applications, moving outward from the center of the surgical area in a spiral pattern.

After allowing the skin to dry for about one minute, firmly press a sterile 6-millimeter punch biopsy at the center of the prepared surgical area. Twist the punch biopsy to create a circular outline on the skin that fully cuts through the skin tissue in at least one section of the outline, taking care not to cut into the underlying fascia or tissue. Then, use sterile scissors and forceps to cut through the epidermis and dermis, following the circular pattern imprinted by the punch biopsy.