title: Regeneration of limb joints in the axolotl (Ambystoma mexicanum).
abstract: In spite of numerous investigations of regenerating salamander limbs, little attention has been paid to the details of how joints are reformed. An understanding of the process and mechanisms of joint regeneration in this model system for tetrapod limb regeneration would provide insights into developing novel therapies for inducing joint regeneration in humans. To this end, we have used the axolotl (Mexican Salamander) model of limb regeneration to describe the morphology and the expression patterns of marker genes during joint regeneration in response to limb amputation. These data are consistent with the hypothesis that the mechanisms of joint formation whether it be development or regeneration are conserved. We also have determined that defects in the epiphyseal region of both forelimbs and hind limbs in the axolotl are regenerated only when the defect is small. As is the case with defects in the diaphysis, there is a critical size above which the endogenous regenerative response is not sufficient to regenerate the joint. This non-regenerative response in an animal that has the ability to regenerate perfectly provides the opportunity to screen for the signaling pathways to induce regeneration of articular cartilage and joints.
authors.affiliation: Department of Developmental and Cell Biology, University of California Irvine, Irvine, California, United States of America.
authors.forename: Jangwoo
authors.initials: J
authors.lastname: Lee
authors.forename: David M
authors.initials: DM
authors.lastname: Gardiner
mesh_terms: D053674:Aggrecans / Q000235:genetics / Q000378:metabolism; D000558:Ambystoma mexicanum / Q000033:anatomy & histology / Q000502:physiology*; D000671:Amputation, Surgical; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002358:Cartilage, Articular / Q000033:anatomy & histology / Q000502:physiology*; D003001:Cloning, Molecular; D024043:Collagen Type II / Q000235:genetics / Q000378:metabolism; D004801:Eosine Yellowish-(YS); D005552:Forelimb / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery; D015870:Gene Expression; D006416:Hematoxylin; D006614:Hindlimb / Q000033:anatomy & histology / Q000502:physiology* / Q000601:surgery; D006651:Histocytochemistry; D018960:Hyaluronan Receptors / Q000235:genetics / Q000378:metabolism; D007596:Joints / Q000033:anatomy & histology / Q000502:physiology*; D012038:Regeneration / Q000502:physiology*
chemical_list: D053674:Aggrecans; D015415:Biomarkers; D024043:Collagen Type II; D018960:Hyaluronan Receptors; D004801:Eosine Yellowish-(YS); D006416:Hematoxylin