Abstract:

Objective To investigate the effect of sodium butyrate on bone mineral content and bone microstructure in mice with fluorosis. Methods According to the principle of weight balance，24 male ICR weaned mice were divided into control group，fluorosis group and sodium butyrate group. The mice in the fluorosis group and sodium butyrate group drank distilled water containing 100 mg/L sodium fluoride，and those in the control group drank water freely. At week 14，the mice in the sodium butyrate group were given 500 mg/kg sodium butyrate by gavage，while those in the control group and fluorosis group were given normal saline. After 20 weeks， the left tibia and femur of the mice in all the groups were removed，which were subjected to bone structure strength measurements，Micro ⁃CT scanning and bone mineral content measurement. Results Compared with the control group，the trabecular bone mineral density，bone volume fraction，bone trabecular number，bone calcium，bone magnesium，bone zinc content and bone structure strength of the mice in the fluorosis group were all significantly decreased（t = 4.921，P < 0.01；t = 6.959，P < 0.01；t = 4.915，P < 0.05；t = 2.363，P < 0.05；t = 6.553，P < 0.01； t = 2.461，P < 0.05；t = 4.166，P < 0.01，respectively），while the trabecular separation，trabecular structure model index，bone fluoride and bone phosphorus content were all significantly increased（t = -3.490，P < 0.05； t = -3.820，P < 0.05；t = -8.608，P < 0.01；t = -8.641，P < 0.01，respectively）. The bone CT results showed that the trabecular structure was sparse and irregular，and the bone micro⁃structures were damaged obviously. The bone trabecular，bone mineral density，bone calcium，bone magnesium，bone zinc content and bone structure strength of the mice in the sodium butyrate group were all significantly higher than those in the fluorosis group （t = -3.557，P < 0.05；t = -2.444，P < 0.05；t = -3.271，P < 0.01；t = -4.810，P < 0.01；t = -2.552，P < 0.05， respectively），while the bone fluoride and bone phosphorus content was also significantly reduced（t = 4.042，P < 0.01；t = 2.424，P < 0.05，respectively）. Our results showed that the structure of trabecular bone was relativelytight，and the degree of structural damage was relatively mild. Conclusion Sodium butyrate can alleviate the disorder of bone metabolism in mice with fluorosis，improve the microstructure of trabecular bone，and enhance the bone strength.

Key words:

sodium butyrate, fluorosis, bone mineral content, bone microstructure