Recent advances in molecular neurobiology include the development of transgenic mice
that express genes encoding fluorescent proteins under neuron-specific promoters (XFP
mice). These mice have been used in the field of developmental neurobiology, but use
has expanded to include the study of peripheral-nerve axonal regeneration subsequent
to crush or unrepaired transection injuries. This report presents a transgenic mouse,
which differs from previously reported and commercially available mice, in that enhanced
yellow fluorescent protein expression (EYFP) is driven by the human thy1 promoter
(hThy1). Motor and sensory peripheral nerves in these mice appear a bright yellow-green
under fluorescent microscopy. This study tracks nerve regeneration in live animals
using a serial imaging system. It also introduces a novel model for examining the
clinically relevant nerve-injury paradigms of tibial nerve transection repaired with
primary neurorrhaphy or graft, and end-to-side neurorrhaphy. Live-animal serial nerve
imaging is compared with wet-mount fluorescent microscopy and histomorphometry in
the same nerve specimens. The use of transgenic mice that strongly express EYFP in
their peripheral neurons, coupled with serial nerve imaging, provide an important
methodology for studying the heterogeneous nature of axonal elongation following peripheral-nerve
injuries.
KEYWORDS
Yellow fluorescent protein - neurorrhaphy - serial imaging - transgenic mice
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Susan E MackinnonM.D.
Division of Plastic and Reconstructive Surgery, Washington University School of Medicine
660 South Euclid Avenue, Campus Box 8238
St. Louis, Missouri 63110-1010
