Atrophy and neuron loss: Effects of a protein‐deficient diet on sympathetic neurons

Protein deficiency is one of the biggest public health problems in the world, accounting for about 30–40% of hospital admissions in developing countries. Nutritional deficiencies lead to alterations in the peripheral nervous system and in the digestive system. Most studies have focused on the effects of protein‐deficient diets on the enteric neurons, but not on sympathetic ganglia, which supply extrinsic sympathetic input to the digestive system. Hence, in this study, we investigated whether a protein‐restricted diet would affect the quantitative structure of rat coeliac ganglion neurons. Five male Wistar rats (undernourished group) were given a pre‐ and postnatal hypoproteinic diet receiving 5% casein, whereas the nourished group (n = 5) was fed with 20% casein (normoproteinic diet). Blood tests were carried out on the animals, e.g., glucose, leptin, and triglyceride plasma concentrations. The main structural findings in this study were that a protein‐deficient diet (5% casein) caused coeliac ganglion (78%) and coeliac ganglion neurons (24%) to atrophy and led to neuron loss (63%). Therefore, the fall in the total number of coeliac ganglion neurons in protein‐restricted rats contrasts strongly with no neuron losses previously described for the enteric neurons of animals subjected to similar protein‐restriction diets. Discrepancies between our figures and the data for enteric neurons (using very similar protein‐restriction protocols) may be attributable to the counting method used. In light of this, further systematic investigations comparing 2‐D and 3‐D quantitative methods are warranted to provide even more advanced data on the effects that a protein‐deficient diet may exert on sympathetic neurons. © 2009 Wiley‐Liss, Inc.