Spiny mice (Acomys) regenerate wounded whisker pad skin with whisker follicles, muscles, and targeted innervation

Abstract

Human skin is repaired by scar formation, lacking hair follicles, arrector pili muscles, and targeted innervation. Scarring leads to significant losses in skin functionality. Contrary to humans, spiny mice (Acomys spp.) repair skin via scar-free regeneration, regrowing hair follicles and muscles. However, skin across the body is diverse, and whether Acomys can regenerate specialized skin remains unclear. Here, we report that Acomys regenerated whisker pad skin with whisker follicles (i.e., vibrissae), blood sinuses, sebaceous glands, skeletal muscles, and targeted innervation. In contrast, CD-1 mice (Mus) healed via scarring and poor innervation of the scar. While whisker pad skin regeneration in Acomys was remarkable, only 20% of whiskers regenerated on average, ranging from 0% to 75%. Regenerated axons were bundled in epineurial sheaths, targeting the regenerated whisker, with an average of 75% of the uninjured innervation. This expands our understanding of Acomys skin regeneration and provides novel models for skin regeneration and sensorimotor recovery.