Objective To detect the early diversification of the bone mineral density in skeletal fluorosis of rabbits by quantitative computed tomography (QCT),and analyze the possible relationship between bone mineral density and bone injury in rabbits with fluorosis.Methods A total of 16 rabbits,half male and half female,were randomly divided into control and experimental groups according to body weight.The two groups of rabbits were given drinking water containing NaF 0 or 300 mg/L,respectively,for 90 days.After the experiment,their bone fluoride content was determined via the fluorine ion-selective electrode method.The alkaline phosphatase (ALP) and osteocalcin (BGP) in serum were measured using enzyme-linked immunosorbent assay (ELISA).Femurl bone mineral density was detected with QCT in vivo.Histopathological changes of femur were observed under light microscope and trabecular acreage was calculated.The results were analyzed with independent-samples t test(t') and partial correlations.Results The bone fluoride content [(3 232.16 ± 927.85) mg/kg],ALP [(42.69 ± 3.28) U/L],BGP concentration [(2 504.19 ± 276.79) μg/L],bone density [(653.49 ± 167.81) g/cm3] and trabecular number [(39.02 ± 3.33)Tb.Ar] of the experimental group were higher than those of control group [(554.01 ± 376.51)mg/kg,(20.50 ± 4.90)U/L,(1 294.60 ± 191.86)μg/L,(540.40 ± 41.99)g/cm3,(8.15 ± 2.34)Tb.Ar],and the differences were statistically significant (t'=7.565,10.641,10.158,2.615,14.494,all P ＜ 0.05).The tissue sclerosis,bone sclerosis and bone texture coarsening were observed through bone mineral density imaging taken by QCT in experimental group.The number of trabeculae increased and the arrangement of tra bec ulae was disorganized.Bone mineral density was positively correlated with bone fluoride,trabeculae,BGP and ALP (r =0.702,0.627,0.614,0.567,all P ＜ 0.05).Conclusions QCT bone density measurement in skeletal fluorosis of rabbits can be used to compute the threedimensional bone density.And it has a good correlation with bone fluoride content,bone histopathological changes and index of bone metabolism in skeletal fluorosis,which suggests that QCT may provide a useful reference for application in patients with skeletal fluorosis.

Objective To investigate the differences of X-ray findings of skeletal fluorosis between coal-burning type endemic fluo-rosis and industrial fluorosis.Methods The patients were randomly selected as research objects including 60 cases of coal-burning type endemic osteofluorosis and 60 cases of industrial osteofluorosis.The X-ray findings on the left forearm,crus and pelvic radio-graphs of these patients were analyzed retrospectively to find out the differences between skeletal fluorosis of coal-burning type endemic fluorosis and industrial fluorosis.Results X-ray features are no significant statistical differences between coal-burning type endemic fluorosis and industrial fluorosis,except these of interosseous membrane ossification of forearm and crus (forearmχ2=10.909,P<0.05;crusχ2=8.547,P<0.05),obturator membrane ossification of pelvis (χ2=36.554,P<0.05),periosteal proliferation outside bone of crus (χ2=4.937,P<0.05),and ossification of soleus (χ2=4.904,P<0.05).Conclusion The X-ray signs of endemic osteofluorosis and industrial skeletal fluorosis are almost similar,but there are some differences between them.

Objective To observe the efficacy and feasibility of transplanting autologous bone marrow mesenchymal stem cells (BMSCs) via articular cavity on skeletal fluorosis rabbits. Methods A total of 30 rabbits, half male and half female, were divided into control group (n=6) and experimental group (n=24) by random number table method. The two groups of rabbits were given drinking water containing NaF 0 or 300 mg/L, respectively. After 90 days, 24 rabbits were divided into single treatment group, multiple treatment group, spontaneous recovery group and treatment solvent control group (6 rabbits in each group, half male and half female). After isolation, the BMSCs from skeletal fluorosis rabbits were cultured and identified, autologous BMSCs were transplanted into rabbit bodies via articular cavity at once or at three different other times, respectively. After 60 days, femur image was observed through X-ray. Femur bone mineral density was measured with quantitative CT (QCT). Serum alkaline phosphatase (ALP) and osteocalcin (BGP) were also measured using enzyme linked immunosorbent assay (ELISA). Bone fluoride content was determined via the fluorine ion-selective electrode method. Histopathology changes of femur were observed through HE staining and the trabecular area was calculated. Results In the multiple treatment group, patchy high-density images of femur were disappeared and abnormal bone texture was recovered compared with that of before transplantation. Bone density [(536.91 ± 25.51) g/cm3], ALP concentration [(20.06 ± 6.25) U/L], BGP concentration [(1230.01 ± 119.50) μg/L], bone fluoride content [(1442.40 ± 458.54) mg/kg] and trabecular area [(27.81 ± 2.90) Tb.Ar] of the multiple treatment group were lower than those of spontaneous recovery group [(635.11 ± 93.42) g/cm3, (43.08 ± 2.82) U/L, (3207.73 ± 788.80) μg/L, (2557.65 ± 173.90) mg/kg, (38.52 ± 2.81) Tb.Ar], and th e differences were statistically significant (P<0.05). HE staining in the multiple treatment group showed that bone marrow cavity was enlarged, and the number of trabeculae was decreased, accompanied by some new generated, neatly arranged normal trabeculae. But similar results were not observed in the single treatment group. Conclusion After multiple transplantation via articular cavity, autologous BMSCs from skeletal fluorosis rabbits could repair the damaged bone tissue and improve the pathological damage of skeletal fluorosis with osteosclerosis.