COLD INJURY TO NERVES IS NOT DUE TO ISCHEMIA ALONE

The effect of cold on nerve fibre populations may be quite selective. Thus it was possible in the present study, with precise timing of a no n-freezing cold nerve injury, to destroy myelinated fibres, but leave unmyelinated fibres intact, The aetiology of this cold-induced selecti ve peripheral nerve pathology remains controversial, but recent eviden ce suggests that ischaemia plays an important role. To investigate thi s matter further, me have sought to determine whether ischaemia alone might account for such discrete nerve pathology, in a series of non-fr eezing cold injury paradigms. Compared with previous 'pure' ischaemic peripheral nerve models, notable differences were found in the present paradigms (early post-ischaemic luxury perfusion and severe nerve pat hology), suggesting a multifactorial aetiology, Nonetheless a tight co rrelation was evident, with increasing duration of cold injury resulti ng in a progressively more severe reduction in post-cold nerve blood h ow Given these findings, we would propose that the pathological basis of non-freezing cold nerve injury is one of ischaemia, accelerated and enhanced by direct cold injury.