Microvessel basement membrane reduplication is not associated with repeated nerve fiber degeneration and regeneration

To determine whether repeated nerve fiber degeneration and regeneration can induce reduplication of endoneurial microvessel basement membranes (BMs), typical of such conditions as diabetic polyneuropathy, electronmicrographs of endoneurial microvessels of rat peroneal and tibial nerves were studied in repeatedly crushed (10 x) sciatic nerves and compared to microvessels of sham-operated uncrushed nerves. On average, crushed nerves had 2.6, SE +/- 0.1 BMs, whereas control nerves had 2.7, SE +/- 0.1 (P > 0.05). Microvessel cellular components were significantly increased in both number and size in the crushed nerves. These nerves also demonstrated a trend to increased vessel numbers and density. These results are not in keeping with the hypothesis that BM reduplication of endoneurial microvessels is simply due to repeated fiber degeneration and regeneration.