慢性氟中毒对大鼠骨组织Dlx5蛋白及其mRNA表达的影响

Effects of chronic fluorosis on expression of Dlx5 protein and mRNA in bone tissue of rats

目的观察慢性氟中毒对大鼠骨组织中转录因子Dlx5蛋白和mRNA表达水平的影响,探讨Dlx5在氟骨症发病机制中的可能作用。方法本研究用36只SD大鼠按性别随机分成3组,对照组(饮自来水,含氟<0.5mg/L)、低氟组(饮含氟5.0mg/L的自来水)、高氟组(饮含氟50mg/L的自来水),6个月后用氟离子选择电极法测定大鼠尿氟及骨氟含量,HE染色观察骨组织病理学改变,并采用原位杂交技术、免疫组织化学方法,对大鼠骨组织进行Dlx5蛋白及mRNA水平的定量分析。结果 HE染色显示染氟大鼠骨组织骨小梁增宽、骨皮质增厚等骨硬化表现;染氟大鼠骨组织Dlx5蛋白及mRNA表达水平显著高于对照组,差异有统计学意义(F低-蛋白=28.381,F高-蛋白=343.515,F低-mRNA=27.767,F高-mRNA=353.987,P均<0.05)。结论过量的氟可上调Dlx5蛋白及mRNA水平的表达,促进成骨细胞的增殖与分化,从而出现骨质硬化。

Objective To observe the effect of chronic fluorosis on the expression of Dlx5 protein and mRNA in bone tissue of rats and to explore the possible role of Dlx5 in pathogenie mechanism of fluorosis. Methods Thirty-six SD rats were randomly divided into low-dose group, high-dose group and control group based on gender, and treated with either 5mg/L or 50mg/L fluoride water solution or only with tap water for 6 months. Then the fluorine levels in urine and bone tissue were measured by elective fluorie method and the pathological change of bone tissue was also observed by HE. Meanwhile the expression of Dlx5 protein and mRNA in bone tissue of rats with fluorosis was analyzed quantitatively by hybridization in situ and immune-histochemistry method. Results The pathologieal examination showed that there were some changes in bone tissue including broadening of bone trabecula and thickening of cortical bone in rats treated with high and low dose fluoride. The expressions of Dlx5 protein and mRNA in Bone tissue were significantly higher than those in the control group, the differences were statistically significant （F= 82.27, 113.18, P〈0. 05）. Conclusions Excessive fluoride may up-regulate the expression of Dlx5 protein and mRNA to promote the proliferation and differentiation of osteoblast in bone tissue, which cause bone sclerosis.