INHIBITORY EFFECTS OF THALIDOMIDE ON CELLULAR PROLIFERATION, ENDONEURIAL EDEMA AND MYELIN PHAGOCYTOSIS DURING EARLY WALLERIAN DEGENERATION

In addition to the well-known teratogenic effect of thalidomide, previ ous studies have revealed mild immunosuppressive properties and, more recently, an antiangiogenic activity. To find out more about the speci ficity of these effects we studied the influence of orally administere d thalidomide on Wallerian degeneration in rats. Wallerian degeneratio n is a potent experimental model for studying reproducible cell prolif eration in vivo. Examination of distal nerve segments of transected sc iatic nerves from rats that had been treated with thalidomide (2 x 250 mg/kg per day) revealed a significant reduction of endoneurial eel co unts at 10-15 days after surgery compared to that seen in controls. Th is effect was not statistically significant, at a very early stage of Wallerian degeneration, i.e., at 5 days after transection of the nerve . Sub-perineurial edema and phagocytosis was also reduced, although th is was not statistically significant. This apparently nonspecific inhi bitory effect of thalidomide during early Wallerian degeneration shown in the present study should be investigated further for its possible relationship to other previously established inhibitory activities of thalidomide, especially its immunosuppressive effect in man.