The relation of bone to the histogenesis of cartilage in regenerating forelimbs and tails of adult Triturus viridescens

Abstract

The organization of thcl urodele limb regenerate is characterizrd by c2 strict ~orre.jpoii~leiice, suggesting a causal relationship, betwc-c.en tlic components of the regenerate and their eonnterparts in the stump. This is most rtrikingly illustrated hy the direct contiiiuity of the old arid the new skeletal elements. lriasiiiuch a s the skeleton is the first tisbue to differentiate in a developing lhstenia, and since bone can be subjected with facility to various experimental techniques, the present account represents a n inquiry into the factors rcsponsiblc for the liistogcriesis of cartilage, with particular reference to the role of bone in this p-ocess.Notwithslanding the spatial, arid perhaps c a u d , relatioilship between corresponding skeletal elements in tlic stiinip and the regenerate, there is considerable evidence that other factors are also involved, for iiuinerous investigators have described normal skeletal regeneration f r o m limbs partially or entirely deprived of ihcir skeletal elements. Extirpation of one of the two bones in t l i c h lower extremity, followed hy amputation through the operat ed region, results in normal reconstitution of the lost parts including regeneration of the

Cartilage and bone cells do not participate in skeletal regeneration in Ambystoma mexicanum limbs

“…However, it was later discovered that the positional information in the internal limb structures is asymmetrically distributed along the proximal/distal limb axis (Gardiner and Bryant, 1989), and consequently these previous surgical manipulations would not be predicted to induce ectopic structures even if this tissue retained positional information. Other experimental differences, such as the age and size of the experimental animals, and whether or not periosteal tissue was included with the grafted tissues, also could underlie the discrepancies among the previous studies (Carlson, 1975;Eggert, 1966;Goss, 1956;Goss, 1958;Kragl et al, 2009;Muneoka et al, 1986;Wallace et al, 1974).…”

“…The amputation of boneless amphibian forelimbs results in the regeneration of the skeletal elements distal to the amputation plane (Goss, 1956;Wigmore 1985), revealing that non-skeletal cells can undergo metaplasia to regenerate skeletal tissue in the limb. Cell lineage studies using dermal-tissue grafts have shown that cells of dermal origin differentiate into chondrocytes and contribute to the regenerated skeleton (Dunis and Namenwirth, 1977;Kragl et al, 2009).…”

“…For example, one test of whether a tissue retains positional information lies in its ability to induce the formation of new pattern (that results in the generation of ectopic structures) when confronted with cells with differing positional information (Endo et al, 2004). Some of the experiments testing this property were conducted on the humerus skeletal element, and because no ectopic structures formed upon 180 o rotation of the humerus, it was concluded that this tissue did not have positional information (Carlson, 1975;Goss, 1956;Wigmore and Holder, 1985). However, it was later discovered that the positional information in the internal limb structures is asymmetrically distributed along the proximal/distal limb axis (Gardiner and Bryant, 1989), and consequently these previous surgical manipulations would not be predicted to induce ectopic structures even if this tissue retained positional information.…”

Limb Regeneration in Axolotl: Is It Superhealing?

“…Some may be tempted to propose that regeneration needs exposure to the outside environment, although the apex of the heart and the spinal cord can regenerate without such exposure and in the presence of surrounding tissues. What is particularly interesting and represents somewhat of a paradox is that bones are completely regenerated if a limb is amputated [5,17,124,125]. The source of cells giving rise to new bones is not likely to be from the bones in the stump [112,118].…”

“…The source of cells giving rise to new bones is not likely to be from the bones in the stump [112,118]. Two series of experiments lend their support to this assertion: first, the rescue of regeneration in irradiated limbs with a graft of healthy skin where all the tissues, except the muscles, are present in the regenerate; and second, the extirpation of the ulna followed by amputation of the limb results in a regenerated limb with a partially regenerated ulna, of the proper dimension and at the proper place, in the newly regenerated portion of the limb, as if the ulna was left in place in the stump [124]. These experiments indicate that in order to regenerate new skeletal elements, material from the elements present in the stump is not needed.…”