Journal of Neuroscience, Vol 10, 2215-2222, Copyright © 1990 by Society for Neuroscience
A comparison of peripheral and central axotomy effects on neurofilament and tubulin gene expression in rat dorsal root ganglion neurons
J Wong and MM Oblinger
Department of Cell Biology and Anatomy, Chicago Medical School, Illinois 60064.
The expression of major cytoskeletal protein mRNAs was studied in adult rat
dorsal root ganglion (DRG) neurons after crushing either their central or
peripheral branch axons. mRNA levels in DRG neurons were examined by
quantitative in situ hybridization with radiolabeled cDNA probes specific
for the low-molecular-weight neurofilament protein (NF- L) and
beta-tubulin. The large-sized (greater than 1000 microns 2) neurons which
give rise to myelinated axons in lumbar ganglia (L4 and L5) were studied 1
d through 8 weeks after either dorsal root or sciatic nerve crush. NF-L and
beta-tubulin mRNA levels in axotomized DRG neurons were compared to those
in contralateral control DRG neurons, as well as to those in normal
(completely untreated) DRG cells. In the case of NF-L mRNA, changes were
observed after central as well as peripheral branch axotomy and the time
course and magnitude of changes were similar after both types of axotomy.
NF-L mRNA levels initially decreased (first 2 weeks after crush) and then
began to return towards control levels at longer survival times. Similar,
but less pronounced, changes in NF-L mRNA levels also occurred in
contralateral DRG neurons (which were uninjured); the changes in
contralateral neurons were not simply a result of surgical stress since no
changes in NF-L mRNA levels were observed in sham-operated DRG neurons. In
the case of tubulin mRNA, changes were observed after central as well as
peripheral branch axotomy by in situ hybridization, but the time course and
magnitude of changes were different after each type of axotomy.(ABSTRACT
TRUNCATED AT 250 WORDS)