Matrix metalloproteinase expression during blastema formation in regeneration-competent versus regeneration-deficient amphibian limbs.

We used an antibody array to compare the protein expression of matrix metalloproteinases (MMPs)-1, -2, -3, -8, -9, -10, and -13, as well as the tissue inhibitors of metalloproteinases (TIMPs)-1, -2, and -4 during blastema formation in amputated hindlimbs of regeneration-competent wild-type axolotls and stage-54 Xenopus, and regeneration-deficient short-toes axolotls and Xenopus froglets. Expression of MMP-9 and -2 was also compared by zymography. Both short-toes and froglet failed to up-regulate MMPs in a pattern comparable to the wild-type axolotl, suggesting that subnormal histolysis is at least in part responsible for the poor blastema formation characteristic of both short-toes and froglet.