The effect of reinnervation on collagen formation in degenerating sciatic nerves of rabbits.

ONE of the phenomena of Wallerian degeneration in peripheral nerves is the formation of new endoneurial collagen. In a previous paper (Abercrombie and Johnson, 1946). we estimated the amount of collagen formed in degenerating sciatic nerves of rabbits during various periods up to two hundred. days after the nerves had been severed. We found that significant amounts of collagen are formed during all periods of degeneration studied. The purpose of the investigation reported in the present paper is to determine whether reinnervation has any effect on this process of collagen formation. To that end we have compared the collagen content of completely severed nerves which undergo degeneration in the absence of reinnervation (these are referred to as non-reinnervated nerves), with the collagen confent of crushed nerves which undergo degeneration but are very rapidly reinnervated (these are referred to as reinnervated nerves). One hundred days were allowed to elapse after the severance or crush before the nerves were removed for collagen estimation; a period during which an easily detectable amount of collagen is formed in normal degeneration.