Effects of Sciatic Denervation on Growth of Hind Limb Bones in Hymenochirus boettgeri

Sohn, Jang Shin; Kim, Hyoung Tae

Abstract

The effect of peripheral nerve on limb growth and maturation has received little attention after the limb differentiation stage. This study investigated the effects of paralysis (loss of function) on growth of bones in the hind limb of Hymenochirus boettgeri. Complete denervation of the right sciatic nerve was performed at stages 63 and 66, animals were sacrificed after 6 and 7 (Groups I and II) and 12 and 13 (Groups III and IV) weeks. Denervation was assessed by degree of paralysis. Specimens were cleared and double stained with alcian blue and alizarin red for cartilage and bone. Length and area of right and left femurs and length of right and left tibia were measured by using an image analyzer program after photographing, and the ratio of right to left femur length and area was calculated. There were no gross morphological differences between the control and sham groups. In the experimental groups, the ratio of femur length was 93.71% and 95.70% in Group I and II, and 96.12% and 96.06% in Group III and IV. The ratio of tibia length was 94.05% and 96.15% in Group I and II, and 98.12% and 98.22% in Group III and IV. The ratio of femur area was 90.43% and 95.61% in Group I and II, and 96.08% and 95.73% in Group III and IV. Comparison between control and experimental groups showed statistically significant (p<0.05). There was a histologically maturational delay in proximal end of denervated hind limb, comparing with opposite side. These results suggested that denervation of sciatic nerve affect directly the growth and maturation of hind limb bones in Hymenochirus boettgeri and loss of critical period of bony maturation after denervation.