Blastema

ic spaces. A blastema (Greek βλάστημα, "offspring" ) is a mass of cells capable of growth and regeneration into organs or body parts. The changing definition of the word "blastema" has been reviewed by Holland (2021).

ic spaces.]] A blastema (Greek βλάστημα, "offspring" ) is a mass of cells capable of growth and regeneration into organs or body parts. The changing definition of the word "blastema" has been reviewed by Holland (2021).

Salamander limb regeneration

When the limb of the salamander is cut off, a layer of epidermis covers the surface of the amputation site. In the first few days after the injury, this wounded epidermis transforms into a layer of signaling cells called the Apical Epithelial Cap (AEC), which has a vital role in regeneration. In the meantime, fibroblasts from the connective tissue migrate across the amputation surface to meet at the center of the wound. These fibroblasts multiply to form a blastema, the progenitor for a new limb. An important model organism for studying limb regeneration is Ambystoma mexicanum (axolotl), a neotenic salamander with exceptional regenerative capabilities. Limb regeneration in these salamanders involves the blastema. Blastema cells, during limb regeneration, experience DNA double-strand breaks and thus require a form of DNA repair referred to as homologous recombination that deals with double-strand breaks. Additionally, blastema cells probably undergo epigenetic alterations during limb regeneration. Salamander blastema cells can differentiate into any cell type with the exception of neurons. This means axons which are cut can be regrown by blastema cells, but if the soma of a neuron is damaged then a new neuron is unable to be created. As a result, neural organs cannot be regenerated.

References

Further reading

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