Zhang Wen-lan, Cui Ya-nan, Gao Shen, Zhang Xiu-yun, Li Guang-sheng
Department of Pathology, Institute of Endemic Disease, Jilin University, Changchun 130021, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2003 Jul;37(4):246-50.
To study expression of proto-oncogenes c-fos and its accompanying gene c-jun in osteoblasts activated by action of excessive fluoride in vivo and in vitro.
Experimental Wistar rats were exposed to sodium fluoride (NaF) added to their drinking water, and NaF was also added in cell culture supernatant for osteoblast-like cells in vitro. Expression of both mRNA and protein of c-fos and c-jun in bone-tissue of rats with chronic fluorosis and cultured osteoblast-like cells were determined by hybridization in situ, Western blot and immunohistochemistry at varied time periods after exposure.
Sodium fluoride could stimulate the proliferation of osteoblast in rats with chronic fluorosis and induce expression of both c-fos and c-jun in all envelops of the spine bone, as compared with its control group. Value of optical absorption in mRNA expression of c-fos and c-jun was 139.63 and 126.37, respectively, in rats with NaF plus high-calcium, significantly lower than that in control group with high-calcium only (107.74 and 117.48, respectively) (P < 0.001). Immunohistochemical analysis showed that protein level of c-fos and c-jun was significantly higher in rats with NaF plus high-calcium than that in control rats with high-calcium only, with values of optical absorption of 139.16, 131.15, 149.98 and 149.19 (P < 0.05), respectively, and protein level of c-fos and c-jun was significantly higher in rats with NaF plus low-calcium than that in control rats with low-calcium only, with values of optical absorption of 117.24, 111.46, 132.46 and 129.79 (P < 0.05), respectively. Western blotting showed that level of protein expression of c-fos and c-jun in periosteal osteoblasts was significantly higher in all rat groups with NaF than that in all control groups, with values of optical absorption of 123.32, 116.60, 115.97 and 108.30, respectively. mRNA expression of c-fos and c-jun in osteoblast-like cells treated with NaF for 12 h increased obviously, and remained at high level 48 h after exposure, with values of optical absorption of 114.80, 161.14, 118.20, and 150.41, respectively, as compared with that in control group (P < 0.001 and P < 0.05).
Exposure to excessive fluoride could stimulate activation and proliferation of both osteoblasts in rats and cultured osteoblast-like cells in vitro, and cause enhanced expression of mRNA and protein of both c-fos and c-jun. Over-expression of c-fos could play an important role in development and proliferation of skeletal lesions in rats with chronic fluorosis.
研究体内外过量氟作用下成骨细胞中原癌基因c-fos及其伴随基因c-jun的表达情况。
将实验性Wistar大鼠饮用添加了氟化钠（NaF）的水，体外培养成骨样细胞时，也在细胞培养上清液中添加NaF。在暴露后的不同时间段，通过原位杂交、蛋白质印迹法和免疫组织化学法测定慢性氟中毒大鼠骨组织及培养的成骨样细胞中c-fos和c-jun的mRNA和蛋白质表达。
与对照组相比，氟化钠可刺激慢性氟中毒大鼠成骨细胞增殖，并诱导其脊柱骨各包壳中c-fos和c-jun的表达。在高钙加NaF的大鼠中，c-fos和c-jun mRNA表达的光吸收值分别为139.63和126.37，显著低于仅高钙对照组（分别为107.74和117.48）（P<0.001）。免疫组织化学分析显示，高钙加NaF的大鼠中c-fos和c-jun的蛋白质水平显著高于仅高钙对照大鼠，光吸收值分别为139.16、131.15、149.98和149.19（P<0.05）；低钙加NaF的大鼠中c-fos和c-jun的蛋白质水平显著高于仅低钙对照大鼠，光吸收值分别为117.24、111.46、132.46和129.79（P<0.05）。蛋白质印迹法显示，所有NaF处理组大鼠骨膜成骨细胞中c-fos和c-jun的蛋白质表达水平均显著高于所有对照组，光吸收值分别为123.32、116.60、115.97和108.30。用NaF处理12小时的成骨样细胞中c-fos和c-jun的mRNA表达明显增加，并在暴露后48小时保持在高水平，光吸收值分别为114.80、161.14、118.20和150.41，与对照组相比（P<0.001和P<0.05）。
过量氟暴露可刺激大鼠体内成骨细胞及体外培养的成骨样细胞的激活和增殖，并导致c-fos和c-jun的mRNA和蛋白质表达增强。c-fos的过表达可能在慢性氟中毒大鼠骨骼病变的发生和增殖中起重要作用。
