Nutritional Deficiency and Wallerian Degeneration in the Rat

Abstract

In the preceding paper (Mannell & Rossiter, 1 9 5 4~) we showed that the concentration of nucleic acid in the sciatic nerve of the rat was a characteristic of the age of the animal (and not of the body-weight), whereas the concentration of phospholipid was a characteristic of the weight (and not of the age). Previously it had been shown that the increase in the concentration of nucleic acid and the decrease in the concentration of phospholipid that takes place after nerve section is more rapid in nerves from younger, and hence smaller, animals (Mannell & Rossiter, 1952, 1954b. These changes are a characteristic of the age of the animal and not of the body-weight.In the experiments described in the preceding paper, differences in body-weight were produced by supplying certain of the animals either with unrestricted quantities of a diet deficient in protein, or with restricted quantities of a diet containing adequate protein. In the latter instance, the daily intake of food was controlled so that the mean body-weight of the animals was maintained at a level similar to that of the animals receiving unlimited amounts of the diet deficient in protein. The results achieved were considered of sufficient nutritional and general biological interest to warrant a study of a completely different type of nutritional deficiency, namely a deficiency of thiamine.Preliminary experiments showed that in thiamine deficiency the general picture was similar to that obtained with a diet deficient in protein, or deficient in total calories. For each type of deficiency, the concentration of nucleic acid in the intact sciatic nerve was related to the age of the animal, and the concentration of phospholipid was related to the body-weight. But with thiamine deficiency there was one notable difference. The decrease in the concentration of phospholipid that occurs in the degenerating peripheral segment after nerve section, which in protein depletion and total calorie deficiency was a function of the age of the animal and not of the body-weight, took place much more slowly than would be anticipated from the age of the animal. In this paper are described further experiments on the effect of supplying a diet deficient in thiamine on the concentration of nucleic acid and phospholipid in the sciatic nerve of the rat and also the effect of the thiamine deficiency on the changes that occur in the concentration of these substances during Wallerian degeneration.

Nutritional Deficiency and Wallerian Degeneration in the Rat

“…After nerve section there is a decrease in the concentration of phospholipid in the peripheral degenerating segment of nerve (Mannell, 1952). This decrease is more rapid in nerves from younger animals (Mannell & Rossiter, 1954), a point illustrated by the finding reported in Table 4 that the decrease in the concentration of phospholipid during the first 8 days after nerve section in nerves from the ' weight controls' was significantly ( P < 0.001, not shown in table) greater than that in nerves Table 5 ... Table 4 also shows that the mean decrease in the concentration of phospholipid in nerves from the protein-deficient animals was not significantly different from that in nerves from the 'age controls', but that it was significantly (P < 0.001) less than that in nerves from the 'weight controls'. Restricting the dietary intake had no significant effect on the decrease in concentration of phospholipid ( Table 5).…”

“…The situation in peripheral nerve is complicated by the finding of Mannell & Rossiter (1952, 1954 that the sciatic nerves of younger, and hence smaller, animals contain a greater concentration of both nucleic acid and phospholipid than the nerves of older, larger animals. In addition, the changes associated with Wallerian degeneration take place more rapidly in the nerves of smaller, younger animals.…”

“…When the sciatic nerve of the rat is sectioned there is an increase in the concentration of nucleic acid in the distal degenerating segment (Mannell, I 952). Mannell & Rossiter (1954) found that, like the concentration of nucleic acid, the increase in the concentration of nucleic acid during the first 8 days after nerve section is greater in nerves from younger rats, This is again demonstrated in the experiments reported in Table 4, where it can be seen that the mean increase in the concentration of nucleic acid in the nerves from the 'weight controls' was significantly (P<o-oI, not shown in table) greater than that in the nerves from the older 'age controls'. Table 4 also shows that the mean increase in nerves from the protein-depleted animals Table 4…”