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Dec. 21, 2004
Contact: Gordon Ovenshine; 724-738-4854; gordon.ovenshine@sru.edu
SRU PROFESSOR RESEARCHES HOW FROGS FREEZE
– AND SURVIVE;
POTENTIAL APPLICATIONS INCLUDE HUMAN
ORGAN TRANSPLANTS
SLIPPERY ROCK,
Pa. – Picture an ice cube. Paint it blue-gray and
you’ve got the gray treefrog in winter, says Dr. Jack Layne,
a Slippery Rock University biology professor whose freeze-thaw
research with frogs shows potential application to human organ
transplants.
Layne studies
how certain species of frogs freeze during winter, becoming so
solid their hearts stop, and then thaw back to normal, able to
reproduce in the spring.
Everyone’s heard of freezing to death. But for the
gray treefrog and three other species Layne studies, the term
doesn’t apply. “It’s just pretty amazing to see
one frozen,” he says. “You would look at it and think
it was dead. But it’s not.”
A “freeze
tolerance” expert, Layne froze 24 frogs at his SRU lab this
month in order to examine their tissues and organs. Working with
students, he is studying how the organs survive the deep freeze and
metabolize again after reviving. He sees potential applications to
the preservation of human organs on their way to transplant
patients.
If doctors
could find a way to freeze and thaw some organs, it could extend
the shelf life or organs for transplants, he says. Currently,
doctors pack organs on ice after removal but they can’t be
frozen because of potential damage to cells.
Layne expects his research to be
published this spring in scientific and medical journals read by
those who study human tissue preservation. Some of his discoveries
could yield clues on discovering a means for freezing human
organs.
Layne,
who has published 50 papers on freeze tolerance, says four species
of frogs freeze and survive: the wood frog, gray treefrogs, spring
peepers and chorus frogs. All four live in southwestern
Pennsylvania.
Outdoors,
the frogs hide themselves barely underground when the temperature
drops below 32 degrees. Ice invades the frog’s arteries and
its heart stops.
Layne
says the frogs survive because their cells are protected by a
natural antifreeze that prevents excessive ice buildup in body
tissues. The chemicals that do this job, glucose and glycerol, are
in the bodies of all animals but freeze-tolerant frogs have these
chemicals at levels that may be hundreds of times higher than in
people.
When the temperature warms, the frogs thaw
in about 12 hours, reviving as if coming out of a coma, then hop
away unharmed. The reproduce in late March or early April, Layne
says. Their emergence from hibernation allows tadpoles to take
advantage of temporary ponds.
Editor’s note: University Public Relations has
digital photographs of Layne’s frozen
frogs.
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