[Change and relationship between Gli1 and β-catenin on rats' bone formation with chronic fluorosis].

Objective

To investigate the change and association of glioma-associated oncogene homolog 1 (Gli1) and β-catenin on bone formation in rats with chronic fluorosis which were inhibited by cyclopamine (Cycl).

Methods

Forty-eight Sprague-Dawley rats were evenly divided to four groups, including control, F, F+Cycl and F+DMSO groups. The control group were fed with tap water (NaF<1 ppm). The F, F+Cycl and F+DMSO groups were exposed to NaF (50 ppm) in drinking water as the chronic fluorosis model. Then the rats in F+Cycl or F+DMSO groups were injected by Cycl or DMSO after 6 months, respectively. Urine fluoride concentration was detected using fluorine ion selective electrode. The enzyme-linked immunosorbent assay (ELISA) was used to detect bone alkaline phosphatase (BALP). Bone tissues were stained with hematoxylin-eosin. The mRNA and protein expression of Gli1 and β-catenin in bone tissue were detected using real-time PCR, immunohistochemistry and Western blot.

Results

Compared with the controls, the urine fluoride concentration and the width and volume of bone trabeculae were increased in the F, F+Cycl and F+DMSO groups, but no statistical difference among the 3 fluorosis groups. The concentration of BALP was increased in the F group and decreased in F+Cycl group (P<0.05). The expression of Gli1 and β-catenin mRNA and protein was higher in the F and F+Cycl groups than controls, but lower in the F+Cycl group than in the F group. There was positive correlation between the expression of Gli1 and β-catenin (r=0.476, P<0.05). The expression of Gli1 and β-catenin was also associated with BALP concentration and volume of bone trabeculae, respectively (r(1)=0.457, r(2)=0.466, r(3)=0.581, r(4)=0.554, respectively, P<0.05 for all).

Conclusions

The expression of Gli1 can be inhibited by Cycl. It may be involved in the bone formation of rats with chronic fluorosis. It may also affect the expression of β-catenin, which is an osteogenesis factor.