Abstract: Objective To study the effects of iodine on osteoblasts in pup rats. Methods Female Wistar rats (n = 20) after pregnancy were randomly divided into four groups: control group Ⅰ, control group Ⅱ, iodine deficient group, iodine overdose group. The control group Ⅰ was fed a normal diet and drank deionized water, while the control group Ⅱ was fed an iodine-deficient diet and drank deionized water with adequate iodine during the experiment. The iodine deficient group was fed an iodine-deficient diet and drank deionized water during the experiment, while the iodine overdose group was fed a normal diet and drank deionized water with high iodine. On gestational day 18, the levels of thyroid hormones and thyroid stimulating hormone were tested in pregnant rats. On postnatal day 0, alkaline phosphatase activities and proliferation of osteoblasts were observed in pup rats. Results The levels of thyroid hormones in iodine deficient group were significant lower than controls(all P<0.05), while the levels of thyroid stimulating hormone increased significantly(all P<0.05). There were no significant differences of the levels of thyroid hormones between the iodine overdose group and controls (all P>0.05). However, a significant upregulation of thyroid stimulating hormone was observed in the iodine overdose group relative to the controls (all P<0.05). The alkaline phosphatase activities and proliferation of osteoblasts were significantly down-regulated in iodine deficient group compared to the other groups (all P<0.05). Conclusion Iodine deficiency in pregnant rats led to downregulation of alkaline phosphatase activities and proliferation of osteoblasts in pup rats.

Key words: Iodine, thyroid hormones, thyroid stimulating hormone, osteoblasts, tooth