OBJECTIVE: To explore the injury mechanism for white matter of spinal cord and the improvement of function after defluoriation.
METHODS: A total of 120 Wistar rats were separated randomly into 4 groups (n = 30 each). High [fluoride] group received high concentration NaF water (200 mg/L) to establish fluorosis model; control group distilled water; deflourination group high concentration NaF water (200 mg/L) for 12 weeks and then distilled water for 12 weeks; defluorination control group. The urinary contents of fluoride were detected at Weeks 4, 8 and 12. The first two groups were sacrificed at Week 12 while the other two groups at Week 24. The spinal cord functions were detected by BBB scale and incline plate test. Their cervical spinal cord tissues were collected and observed under electron microscope. The expression of myelin basic protein (MBP) in thoracic cord was detected by immunohistochemistry and Western blot. The comparison of measurement data was performed with F test and correlation analysis. Cytological changes of white matter in spinal cord were detected after chronic fluorosis.
RESULTS: The spinal functions of high [fluoride] and deflourination groups were inferior to those of the control groups. But no difference existed among the groups. Pathological manifestations of chronic white matter injury of spinal cord could be found in high [fluoride] and deflourination groups. The MBP expression in spinal cord of fluorosis and deflurination groups decreased in comparison with those in control groups. But no difference existed among them.
CONCLUSION: White matter injury of spinal cord is present in chronic fluorosis rats. Defluoriation for a short time offers no recovery.