DELAY OF CNTF DECREASE FOLLOWING PERIPHERAL-NERVE INJURY IN C57BL WLDMICE/

In peripheral nerves, ciliary neurotrophic factor (CNTF) is localized to a subset of Schwann cells and is decreased in synthesis during Wall erian degeneration, This pattern of expression is similar to that of m yelin protein genes. In the present study, CS7BL/Wld mice, which exhib it delayed Wallerian degeneration, were used to determine the role of axonal contact on the regulation of CNTF synthesis. Western blot analy sis showed that CNTF immunoreactivity in Wld nerves remained almost no rmal even 10 days after ligation when it was almost undetectable in co ntrol mice. Reverse transcriptase polymerase chain reaction (RT-PCR) a nalysis revealed that 4 days after ligation, concentrations of CNTF mR NA in Wld mice had decreased much less than in control mice, but that at 10 days CNTF mRNA concentrations in Wld and control mice were compa rably low These observations suggest that maintenance of axonal contac t in the absence of axonal transport from the cell body delays the dec rease of CNTF mRNA normally seen after injury. Also, during Wallerian degeneration in Wld mice, the decrease of CNTF protein is delayed for many days longer than the decrease in CNTF mRNA. (C) 1997 Wiley-Liss, Inc.