[Morphometric study of bone in domestic pigs with fluorosis caused by coal-burning pollution]

Forty four domestic pigs were divided into 2 groups: control group: 17 pigs; fluorosis group: 27. They were fed for 14 months in the endemic area or non-endemic area respectively. In some of the pigs, double tetracycline was given for bone dynamic study, and blood and urine were collected for biochemical analyses. Iliac, tibia, fibula, the 2nd metatarsal and the 2nd vertebrae were reserved either for bone density measurement or for bone histomorphometric study. The results showed that fluoride content either in serum and in urine or in bone tissue was significantly elevated. The bone density of tibia was increased. Bone histomorphometry showed that trabecular bone volume of iliac and vertebrae was increased while that of fibula head was decreased. Trabecular resorption surface of fibula head was expanded while that of vertebrae was shrunk. As to bone dynamics, both bone formation rate and bone mineralization rate were inhibited, indicating that the toxic effects of fluoride in tremendous amount on bone remodeling. The authors suggest that the existence of osteosclerosis of axial and osteoporosis of peripheral bone in fluorosis might be related to the redistribution of calcium within the body. Furthermore, fluoride may be an osteomalacic factor for the development of osteomalacia in endemic fluorosis.