Blastema Volume And Nuclear Size In The Regenerating Hind Limbs In Larvae Of Xenopus Laevis And Bufo Regularis After Transection At The Ankle Level

Abstract

After amputation at the ankle level of hind limbs in larval Xenopus laevis and Bufo regularis, an increase in the nuclear volume of blastema and stump tissue cells was observed. The cells in the distal region of blastema appeared to have the largest nuclei throughout the whole regenerating limb. In the stump, the increase in the nuclear volume was mostly confined to the distal region close to the amputation site, and a proximodistal gradient was pronouced. This might explain that amputation increased the metabolic activities of the stump tissue cells. There was a general indication that the nuclear volume value was higher in Xenopus than in Bufo. Measurments of blastema and stump volumes revealed that although the blastema size at the late larval stage 57 was larger than that of the early stage 53; yet the value of blastema volume relative to stump volume was much higher at the early stage. This value was significantly larger in Xenopus than in Bufo. The nuclear volume was positively correlated with blastema volume at stage 53, whereas at stage 57, this correlation was negative. This may indicate that the mesenchymal blastema size seems to be a reflexion to the nuclear size, than to the intercellular substance.