The effect of perinatal undernutrition on perineurial diffusion barrier to exogenous protein

Summary The maturation of the perineurial diffusion barrier to exogenous protein was studied fluorescence-microscopically on sciatic nerve in normal, undernourished and rehabilitated rats. Bovine albumin labelled with Evans blue was used as tracer and applied around the sciatic nervein vivo for 1 h and for 24 h.It was shown that in normal rats the perineurial diffusion barrier to protein is established at the age of 4 weeks and after this age no diffusion through the perineurium into the endoneurial spaces takes place.In rats subjected to pre- and postnatal undernutrition no effective barrier was present during the observation-period extended to 4 months, indicating an impaired maturation of the perineurial diffusion barrier.Rats rehabilitated by foodad libitum, even from the early age of 5 days, revealed no effective barrier to protein when examined at the age of 3 months. It is concluded that pre-and postanatal undernutrition causes a damage to the perineurium functionally manifested as a deficient barrier to exogenously applied protein.