Abstract: ObjectiveTo observe the ex pression of OPG,OPGL in bone of fluorosis rats caused by coal burning and to explore the effects of skeletal fluorosis and osteoprotegerin and steoproteger in ligand.MethodsSDrats taken as the experimental objects were randomly assorted into 5 groups(the number either female or male was the same in each group):control group,high-dose fluoride group,high-dose fluoride group-emented with low calcium diet group,low-dose fluoride group,low-dose fluoride supplemented with low calcium diet group.All rats were fed with corndried by burning coal,which came from the borough with high prevalence of fluoride,to establish the animal model of fluorosis.The tibia slices of chronic fluorosis rots were stained vith HE;OPG、OPGL in tibia metaphysis were observed by immuno histochemistry.ResultsCompared with control group,the number of OPG increased in every test group and the difference was statistically significant(P<0.05).Compared with high-dose fluo ride group and low-dose fluo ride group the increase of OPCL expression in highdose fluoride supplemented with low calcium diet group and low-dose fluoride supplemented with low calcium diet group was statistically significant(P<0.05).The compact bone of the cortex of high-dose fluoride supplemented with low calcium diet group become porosity.ConclusionExcessive fluoride caninduce accelerative bone turnover and enhance the activity of osteoclastic absorption by increasing the OPCL.Low calcium diet can promote bone absorption of skeletal fluorosis.