缺锌抑制体外培养大鼠成骨细胞的增殖及分化

为了研究缺锌对体外培养大鼠成骨细胞增殖和分化的影响，从大鼠颅骨分离出成骨细胞，并于ＤＭＥＭ培养基中进行传代培养。锌特异性络合剂ＴＰＥＮ络合掉培养基中的锌建立细胞体外培养的缺锌模型。采用３Ｈ－ＴｄＲ掺入法确定成骨细胞在不同时点ＤＮＡ的合成状况，同时应用流式细胞仪进行细胞周期的分析；采用组织学方法观察细胞骨架的变化、３Ｈ－脯氨酸掺入法确定胶原蛋白的合成；采用酶动力学和放免方法分别测定碱性磷酸酶活性和骨钙素含量。结果表明，缺锌组成骨细胞３Ｈ－ＴｄＲ掺入量在各个时点明显低于对照组，细胞被阻滞于细胞周期中Ｇ２／Ｍ期，这与细胞骨架受损密切相关。缺锌组胶原蛋白合成、骨钙素含量及碱性磷酸酶活性明显低于对照组。但缺锌补锌组的各个指标与对照组相比无统计学差异。因此，缺锌能够抑制体外培养大鼠成骨细胞的增殖和分化。

Zinc deficiency inhibited the proliferation and differentiation of rat osteoblast in vitro

The effect of zinc deficiency on proliferation and differentiation of rat osteoblast was studied in vitro. The osteoblasts were isolated from the rat calvaria, and were subcultured in DMEM medium. Zinc deficiency model in cell culture was made by chelating zinc from the medium with a special chelator TPEN. Incorporation of 3H thymidine was measured to show the DNA synthesis at different time point, and cell cycle was analyzed by flow cytometry. A histochemistry method was used to detect changes of osteoblast cytoskeleton. Incorporation of 3H proline was measured to show the synthesis of collagen. Alkaline phosphatase activity (AKP) and osteocalcin content were measured by enzyme dynamics method and radioimunoassay respectively. The results showed that the incorporation of 3H thymidine in the zinc deficient group was significantly less than that in the control group at different time points. The cells were blocked at G2/M phase of cell cycle, which is related to the impairment of cytoskeleton. Collagen synthesis, osteocalcin content and AKP activity in the zinc deficient group were reduced significantly as compared with those in the control group. But no differences in all the measurements were observed between the control group and the group of zinc deficiency supplemented with zinc. Therefore, it was concluded that zinc deficiency inhibited the proliferation and differentiation of rat osteoblast in vitro.