Abstract: PURPOSE: This study was to investigate the expression of survivin in dental germ development of SD rats with fluorosis, and explore the effects of fluoride on survivin expression and the pathogenic mechanism of dental fluorosis. METHODS: Forty-five SD rats (pregnant for 10 days) were randomly divided into control group, experimental group 1 and group 2. Drinking water with fluoride concentration of 0, 50, 150 mg/L was provided for rats accordingly. The samples were collected at E18.5th day, E20.5th day, P1.5th day, P3.5th day and P5.5th day, then the samples of P1.5th day were selected for H-E staining. SABC method was used for immunohistochemical analysis of samples in each group. The images were acquired by Motic Med 6.0 digital medical image analysis system, and the data were analyzed for ANOVA with SPSS 13.0 software package. RESULTS: Survivin expression fluctuated and exhibited 'M' shape (rose first and fell later) in each group.There was no significant difference at E18.5th day (F=1.050, P>0.05) and E20.5th day (F=2.232, P>0.05) between each group. There were significant differences at P1.5th day (F=3.538, P<0.05), P 3.5th day (F=3.820, P<0.05) and P5.5th day (F=5.096, P<0.05) between the control and experimental groups. The postnatal rats in each group were evaluated by SNK method for surviving expression. There was no significant difference between control group and experimental group 1 (P>0.05). However, there was significant difference between control group and experimental group 2 (P<0.05). CONCLUSIONS: The results suggest that fluoride can decrease the expression of survivin in the postnatal rats with higher fluoride concentration, which may be the mechanism in the development of dental fluorosis.

Key words: Survivin, SD rat, Fluorosis, Tooth development