Tail regeneration and other phenomena of wound healing and tissue restoration in lizards

Abstract

Wound healing is a fundamental evolutionary adaptation with two possible outcomes: scar formation or reparative regeneration. Scars participate in re-forming the barrier with the external environment and restoring homeostasis to injured tissues, but are well understood to represent dysfunctional replacements. In contrast, reparative regeneration is a tissue-specific program that near-perfectly replicates that which was lost or damaged. Although regeneration is best known from salamanders (including newts and axolotls) and zebrafish, it is unexpectedly widespread among vertebrates. For example, mice and humans can replace their digit tips, while many lizards can spontaneously regenerate almost their entire tail. Whereas the phenomenon of lizard tail regeneration has long been recognized, many details of this process remain poorly understood. All of this is beginning to change. This Review provides a comparative perspective on mechanisms of wound healing and regeneration, with a focus on lizards as an emerging model. Not only are lizards able to regrow cartilage and the spinal cord following tail loss, some species can also regenerate tissues after full-thickness skin wounds to the body, transections of the optic nerve and even lesions to parts of the brain. Current investigations are advancing our understanding of the biological requirements for successful tissue and organ repair, with obvious implications for biomedical sciences and regenerative medicine.

Appendage regeneration in anamniotes utilizes genes active during larval‐metamorphic stages that have been lost or altered in amniotes: The case for studying lizard tail regeneration

“…The study on the regenerative capabilities in lizards has been largely neglected during the entire history of regeneration studies, and only few researchers have analyzed this unique amniote model of organ regeneration (Marcucci, 1930; a large bibliographical list is reported in Bellairs & Bryant (1985); Alibardi, 2010Alibardi, , 2014Alibardi, , 2017aAlibardi, , 2020aHutchins, Eckalbar, et al, 2016;Jacyniak, McDonald, & Vickaryous, 2017).…”

The relationship between body shape, body size and locomotor mode in extant lepidosaurs

“…Facultative bipedality has been associated with a long tail and a low intermembral index ([Humerus + Radius] Ä [Femur + Tibia]) in the fossil record of Archosauria (Galton, 1973;Padian, 2008;Persons & Currie, 2017), Lepidosauria (Simões et al, 2017) and in extant squamates (Snyder, 1962;Irschick & Jayne, 1999a). The use of tail dimensions for the identification of facultative bipedality presents a challenge when working with museum specimens alone, as many specimens are either missing tails or have regenerated tails not indicative of the original bony structure (Jacyniak, McDonald & Vickaryous, 2017). As such, using inaccurate tail length to identify anatomies associated with facultative bipedality can be misleading.…”

Transcriptome and Proteome analysis ofHemidactylus frenatusduring initial stages of tail regeneration

“…The mass of undifferentiated cells (blastema) surrounding the injured tissue results in the formation of fully functional replica which enacts the phenomenon of epimorphic regeneration [1]. The ability to regenerate a full limb is absent in mammals but urodeles; teleost and amniotes have the propensity to replace limbs, spinal cords, nervous system, heart, tail and, other body parts [2]. To understand the mechanistic framework of regeneration, researchers have been majorly associated with urodeles amphibians [3]; teleost fishes [4].…”

“…Though amniotes i.e. lizards are closely related to mammals and other vertebrates, very little attention has been given to carry out regeneration on this organism [2], [5].…”