Experimental model of pyridoxine (B-6) deficiency-induced neuropathy

A pyridoxine (B-6) dietary deficiency was studied in female adult Sprague-D awley rats by hind-limb walking-track analysis. Serum levels of pyridoxine and three metabolites were quantified by high-pressure liquid chromatograph y with fluorescence measurement. Morphometric analysis of the sciatic and p osterior 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 we re 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 c orrected these parameters, whereas the addition of 30 parts per million B-6 corrected the abnormal pattern completely. Serum pyridoxal concentration c orrelated with the functional parameters, dropping from a mean of 115 mg pe r liter to 39.5 mg per liter (p < 0.05), and correcting with the B-6 additi ve. Morphometric analysis demonstrated that the B-6-deficient nerve from th e tarsal tunnel had a decreased nerve fiber density (p < 0.001), with a nor mal total myelinated nerve fiber number, and an increased axon-to-myelin ra tio (p < 0.003). It is concluded that a diet totally deficient in vitamin B -6 results in a peripheral neuropathy.