Cutaneous nerve degeneration induced by acrylamide in mice.

Acrylamide is a neurotoxin producing distal axonopathy. Previous studies mainly focused on large-diameter motor and sensory nerves, and the influences of acrylamide neurotoxicity on small-diameter sensory nerves in the skin remained elusive. We investigated skin innervation in mice intoxicated by acrylamide. Small-diameter sensory nerves in the skin degenerated after acrylamide intoxication. Epidermal nerve swelling was the earliest sign of acrylamide intoxication, with 29.5+/-2.4% of swollen epidermal nerves in the initial stage (P<0.001). There was a trend of progressive loss of epidermal nerves with a significantly reduced epidermal nerve density in the late stage (P<0.003). In the mean time, degenerating dermal nerves exhibited a beaded appearance. These results suggest the scenario of small-diameter cutaneous nerve degeneration in acrylamide neurotoxicity: beginning with epidermal nerve terminal swelling in the initial stage and resultant epidermal nerve depletion in the late phase.