Abstract: Objective To explore the effect of sodium chlorite(NaClO₂)on neurodevelopmental toxicity in rats.Methods Specific-pathogen-free(SPF) Wistar rats were randomly divided into low,moderate,and high dose of NaClO₂ group and a negative control group by weight.The rats in NaClO₂ groups were continuously exposed to NaClO₂ through drinking water for 63 days after the birth.The brain,cerebellum and hippocampus of the rats were observed with histopathological examination,and the concentrations of serum S100B protein and myelin basic protein(MBP) were detected with enzyme-linked immunosorbent assay(ELISA).Results The rats' ratios of brain,cerebellum,and hippocampus to their body in exposure groups were not significantly different compared with those of the control group.The number of cerebellar Purkinje nerve cells of exposure groups decreased and the arrangements of the cells were sparse based on histopathological examination.The cerebellum and brainstem white matter in the third generation rats of high-dose group showed spotty demyelinating lesions.Compared with the control group,both the serum MBP of the high dose group(6.83?0.64,7.55?1.42,and 5.03?0.67 pg/ml for the rats of first,second,and third generation) and the serum S100B protein concentration(36.80?8.45,45.85?6.58,and 43.20?7.48 pg/ml for the rats of first,second,and third generation) increased significantly(P<0.05 for all).With the increasing NaClO₂ dose and exposure time,the levels of MBP and S100B protein in the rats of different generations increased with dose-response relationship(P<0.05).Conclusion Drinking the water with high concentration of sodium chlorite can cause increases of serum MBP and S100B in the offspring rats,resulting in decrease in the number of Purkinje cell and damage of brain glial cell and myelin in the brain tissue.