Regeneration breakthrough in mice

From ANIMAL PEOPLE, March 1998:

PHILADELPHIA––The key to human
regrowth of lost or injured limbs and organs may
have been found by accident in connection with
genetically modifying mice for disease research,
immunologist Ellen Heber-Katz of the Wistar
Institute indicated in a February 16 address to the
American Association for the Advancement of
Science.
Heber-Katz was studying multiple sclerosis
using the fairly common MRL strain of custom-bred
research mouse, she said, when she
found that ID holes punched in her subjects’ ears
quickly healed over without a trace. Removing
bits of their tails and livers brought similar
results: new parts grew, matching the old.

Scarless regrowth of body parts has previously
been seen only in frogs. Partial regeneration
has been achieved in mammals with electrical
stimulation, but only in very young subjects.
Heber-Katz believes the MRL mice
have the capacity for perfect tissue regrowth
because they lack a subset of immune system Tcells
which as well as protecting the host animals
from certain kinds of disease also seem to block
the repair process as it occurs in amphibians.
Heber-Katz said her team has now identified
seven possible areas within the genetic
structure of the MRL mice which might contain
the genetic secrets of tissue regeneration. They
are also undertaking experiments to see if the
process can also repair damaged nerve tissue.
The work has promise in healing limb
loss, severe burns, and spinal cord injuries,
Heber-Katz suggested. But it also indicates many
painful times ahead for MRL mice during the
coming years of investigation.