Oral-facial tissue reconstruction in the regenerative axolotl

Abstract

Absence of large amounts of orofacial tissues caused by cancerous resections, congenital defects or trauma result in sequelae such as dysphagia and noticeable scars. Oral-neck tissue regeneration was studied in the axolotl (regenerative amphibian) following a 2.5mm punch biopsy that simultaneously removed skin, connective tissue, muscle, and cartilage in the tongue and intermandibular region. The untreated wound was studied macroscopically and histologically at 17 different time points ranging from 0-180d (N= 120 axolotls). At 12h the wound’s surface was smoothened and within 1mm, internal lingual muscular modifications occurred; at the same distance, between days 4-7 lingual muscle degradation was complete. Immunofluorescence indicates complete keratinocytes migration by 48h. These cells with epidermal Leydig cells, appearing yellow, lead the chin’s deep tissue outgrowth until its closure on the 14th day. Regeneration speeds varied and peaked in time for each tissue, 1) deep Immunofluorescence to Col IV showed basement membrane reconnected between days 30-45 coinciding with the chin’s dermal tissue’s surface area recovery. New muscle appeared at 21d and was always preceded by the formation of a collagen bed. Both chin tissues regain all surface area and practically all components while the lingual structure lacks some content but is generally similar to the original. The methodology and high-resolution observations described here are the first of its kind for this animal model and could serve as a basis for future studies in oral and facial regenerative research.