Experimental model of pyridoxine (B6) deficiency-induced neuropathy

A pyridoxine (B-6) dietary deficiency was studied in female adult Sprague-Dawley rats by hind-limb walking-track analysis. Serum levels of pyridoxine and three metabolites were quantified by high-pressure liquid chromatography with fluorescence measurement. Morphometric analysis of the sciatic and posterior tibia[ nerves (from within the tarsal tunnel) was performed after I year on a diet deficient in vitamin B-6. The B-6-deficient rats developed abnormal walking-track patterns by 8 months, and these track parameters were different from age- and sex-matched normal diet control rats at the p < 0.05 level. Adding B-6 at 10 parts per million to the diet then partially corrected these parameters, whereas the addition of 30 parts per million B-6 corrected the abnormal pattern completely. Serum pyridoxal concentration correlated with the functional parameters, dropping from a mean of 115 mg per liter to 39.5 mg per liter (p < 0.05), and correcting with the B-6 additive. Morphometric analysis demonstrated that the B-6-deficient nerve from the tarsal tunnel had a decreased nerve fiber density (p < 0.001), with a normal total myelinated nerve fiber number, and an increased axon-to-myelin ratio (p < 0.003). It is concluded that a diet totally deficient in vitamin B-6 results in a peripheral neuropathy.