Effects of a conditioning lesion on bullfrog sciatic nerve regeneration: Analysis of fast axonally transported proteins

We have shown that bullfrog sciatic nerves respond to a conditioning lesion similarly to goldfish optic nerve and rat or mouse sciatic nerve; that is, following a crush the rate of regeneration is faster in nerves that have received a conditioning lesion compared to nerves that have not. Also, damaged nerve fibres show initial growth or sprouting earlier in a previously conditioned nerve compared to nerves that have not received a prior conditioning lesion. We have not detected changes in the transport of fast axonally transported proteins with the conditioning lesion paradigm, other than those changes seen in regenerating nerves after receiving a single lesion. However, more label was present in a few axonally transported proteins at the lesion site in conditioned nerves compared to nonconditioned nerves, and this difference is not apparently due to increased transport. It seems that changes in fast axonally transported proteins probably do not contribute directly to the mechanism underlying the conditioning lesion effect of higher out growth rates, although some of the fast transported proteins may be involved in functions, possibly at the growing tip of damaged fibres, which promote or result from the conditioning effect.