The difference in the timing of the regeneration process of skeletal
muscle between SJL/J and BALB/c mice
was investigated using grafts of whole skeletal muscle (both autografts
and
allografts). Histological,
autoradiographic and immunohistochemical techniques were used in the
investigation. Infiltration of
leucocytes into autografts, numbers of desmin-positive myogenic cells and
myotube formation were all more
advanced in the SJL/J compared with BALB/c mice. Furthermore,
autoradiographic evidence showed that
myoblasts in the SJL/J autografts were synthesising DNA 12 h earlier
than myoblasts in BALB/c
autografts. In allografts, where SJL/J host mice received BALB/c
grafts, and vice versa, leucocyte
infiltration and myotube formation occurred earlier in the BALB/c muscles
grafted into SJL/J hosts, than
in the reverse situation with BALB/c hosts. The results show that,
at
least for whole muscle grafts, it is the
host environment which determines the speed and outcome of the regenerative
process.