RESUMO
Objective To study the effect of fluorine on the bone histomorphometry of humbar in rats.Methods Ninety 2-month-old SPF Sparague-Dawley rats,half male and female,were randomly divided into 9 groups:control[(childhood(CS),adult(AS),long-time(NS)]group and drug group[childhood high-fluoride and low-fluoride group(CHS,CLS),adult high-fluoride and low-fluoride(AHS,ALS),long-term high-fluoride and low-fluoride(CLHS,CLLS)].The control group was administered orally with solution of 0.9%NaCl,while the drug group was given orally with different dose of NaF at the same time. Sections of the fifth lumbar were made which was undecalicified for bone histomorphometric analysis, including the percentage of trabecular bone area (% Tb.Ar),trabecular thickness(Tb.Th), trabecular number(Tb.N), trabecular separation(Th.Sp) ; broken trabecular bone area cells (Oc.N), osteoclast perimeter percentage (% Oc.Pm), the percentage of labeled perimeter (% L.Pm), bone mineral apposition rate(MAR), osteoblast perimeter(Ob.PM), trabecular bone perimeter formation rate (BFR/BS),trabecular bone area formation rate (BFR/BV), the total area of bone formation rate (BFR/TV). Results [1]The percentage of Tb.Ar, Tb.Th, Tb.N,%L.Pm, MAR, BFR/BS, BFR/BV and BFR/TV of CHS group [(50.63 ±7.44)%, (150.26 ± 27.51 )μm, (3.44 ± 0.47)N/mm, (50.63 ± 7.44)%, (0.85 ± 0.03)μm/d, (8.45 ± 2.36)μm/d ×100, (381.16 ± 41.62)%/year, (75.07 ± 4.81)%/year] was higher than that of CS group [(29.71 + 9.32)%,(110.93 ± 28.19)μm, (2.68 ± 0.34)N/mm, (24.00 ± 1.22)%, (0.65 ± 0.03)μm/d, (5.43 ± 0.18)μm/d × 100,(141.32 ± 9.29)%/year, (58.14 ± 2.3)%/year, all P < 0.05)]. The %Tb.Ar, Tb.Th, %L.Pm, MAR, BFR/BS,BFR/BV, BFR/TV and Ob.PM of CLS group [(40.76 ± 6.43)%, (164.25 ± 45.65)μm, (42.02 ± 6.12)%, (0.85 ±0.04)μm/d, (8.95 ± 3.73)μm/d × 100, (378.73 ± 35.39)%/year, (73.52 ± 8.71)%/year, (1.41 ± 0.05)μm] were increased (all P < 0.05). [2]Compared with AS group, the %Tb.Ar,Oc.N, %Oc.Pm, %L.Pm, MAR, BFR/BS,BFR/BV and BFR/TV of AHS group[ (50.62 ± 5.76)%, (0.51 ± 0.05)N/mm, (1.13 ± 0.05)%, (42.3 ± 7.02)%,(1.28 ± 0.09)μm/d, (12.91 ± 1.52)μm/d × 100, (390.12 ± 43.56)%/year, (65.21 ± 22.13)%/year] was higher than that of AS group[ (42.73 ± 5.22)%, (0.41 ± 0.17)N/ram, (0.77 ± 0.52)%, (28.43 ± 6.93)%, (0.80 ± 0.03)μm/d, (9.83 ± 1.44)μm/d × 100, (324.43±53.44)%/year and(48.35 ± 9.36)%/year, all P < 0.05)] . The %Tb.At, Oc.N, %Oc.Pm, %L.Pm, MAR, BFR/BS, BFR/BV and BFR/TV of ALS group [(51.14 ± 6.22)%, (0.49 ±0.61)N/mm, (1.17 ± 0.11)%, (45.06 ± 6.92)%, (1.39 ± 0.08)μm/d, (12.87 ± 1.35)μm/d × 100, (394.6 ±50.23)%/year and(66.31 ± 18.93)%/year] were higher than that of AS group(P < 0.05) .[3] The Ob.PM ,Oc.N and %Oc.Pm of CLHS group[ (1.47 ± 0.27)μm, (0.58 ± 0.13)N/mm, (1.14 ± 0.07)%] were obviously increased(P <0.05), as compared with NS group [ (0.82 ± 1.20)μm, (0.42 ± 0.25)N/mm and (0.75 ± 0.64)%, all P < 0.05].Conclusions The short-term administration of NaF on rats in the growing period increases the bone formation and osteoblast activities of young rats and adult rats. The long-term administration of NaF on rats does not increase the bone formation of rats in growth period. The osteoblast activities as well as the bone absorption of lumbar vertebra were strengthened. The likelihood of bone fracture became larger. The negative effects on bone metabolism and bone quality of rats were gradually displayed along with the prolongation of sodium fluoride usage.