Expressions of transforming growth factor-β1 and interleukin 6 mRNA and protein in bone of rats with chronic fluorosis / 中华地方病学杂志

ABSTRACT

Objective To investigate the significance of osteo-immunology related factor transforming growth factor-β1 (TGF-β1) and interleukin 6 (IL-6) in bone of rats with chronic fluorosis.Methods Thirty-six healthy SD rats were divided to three groups according to body weight with the method of random digits table.The rats of control were fed with tap water(NaF ＜ 1 mg/L) and the experimental rats were exposed to NaF (lower dose group5 mg/L,higher dose group50 rmg/L) added to the drinking water to establish the chronic fluorosis model.All rats were killed on the six months and the metaphysic of femoral was collected.Bone fluorine was detected by ashing-fluorin ion selective electrode method.Bone tissues were stained with hematoxylin-eosin and observed under optical microscope.The content of bone alkaline phosphatase (BALP) in rat serum was detected by enzyme-linked immunosorbent assay(ELISA).The expressions of TGF-β1 and IL-6 mRNA and protein in bone were detected by in situ hybridization (ISH) and immunohistochemistry (IHC).Results The contents of bone fluorine were increased gradually in the control,the lower and higher doses fluoride groups[(306.04 ± 12.57),(652.91 ± 51.83),(1 094.11 ± 91.41)mg/kg,F =31.14,P ＜ 0.05].Bone sclerosis could be observed under optical microscope in lower and higher dose groups.The content of BALP in serum increased with the dose of fluoride gradually in the control,the lower and higher doses fluoride groups[(27.78 ± 4.09),(46.59 ± 5.75),(57.45 ± 3.99)U/L],expressions of mRNA (111.84 ± 4.62,123.86 ± 7.46,140.83 ± 5.21) and protein (118.60 ± 7.09,133.17 ± 7.33,145.67 ± 9.61) of TGF-β1 were both increased(F =30.29,73,28,33.65,all P ＜ 0.05).The expressions of mRNA(117.78 ± 7.01,119.90 ± 5.10) and protein(122.79 ± 6.49,123.81 ± 7.99) of IL-6 were both higher than those of the control (106.49 ± 6.76,112.11 ± 5.80,F =15.47、10.83,all P ＜ 0.05).Conclusion The expressions of osteo-immunology related factor TGF-β1 and IL-6 in bone of rats with chronic fluorosis have changed,which indicates that fluoride can impact the increased bone formation by regulating the micro environment of bone.