Application of benchmark dose (BMD) in a bone-effect study on a general population environmentally exposed to cadmium / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To estimate the benchmark dose for osteoporosis caused by cadmium exposure in a Chinese general population with an epidemiological study.</p><p><b>METHODS</b>The inhabitants living in both cadmium polluted and non-polluted areas served as the exposure group and the control group. Urinary cadmium (UCd) and Blood cadmium (BCd) were used as exposure biomarkers while the Z score was used as effect biomarker for the osteoporosis.</p><p><b>RESULTS</b>The UCd and BCd in the habitants of the polluted areas were significantly higher than those in the habitants of the control area on average (P < 0.05) and the UCd and BCd in the habitants of the highly polluted areas were significantly higher than those in the habitants of the moderately polluted area on average (P < 0.05). The bone mineral density was significantly decreased in the groups of the highest UCd and BCd level compared with the 5 microg/g Cr group with the significant difference (P < 0.05). The morbidity of the osteoporosis would increase significantly with the increase of the cadmium exposure (P < 0.05) with the linear correlation (P < 0.05). BMDs were calculated using BMDS Version l.3.2 software and BMDLs were also determined. The BMDL of UCd for cadmium-induced osteoporosis was higher than those representing cadmium-induced renal dysfunction.</p><p><b>CONCLUSION</b>High level of cadmium exposure can induce osteoporosis, which occurs later than renal damage related to cadmium exposure. The BMD is a practical method.</p>

Therapeutic effect of recombinant human parathyroid hormone(1-34) on osteoporosis of ovariectomized rats / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the therapeutic effect of recombinant human parathyroid hormone(1-34) [rhPTH(1-34)] on osteoporosis of ovariectomized rats.</p><p><b>METHODS</b>The model of osteoporosis was formed after 3 months of ovariectomy with 6-month age of 80 rats. Another 20 rats was control of sham operation. rhPTH(1-34) was subcutaneously injected once daily with 5, 10, 20, 40 micrograms/kg for 3 months. There were 10 rats in each group. The control of therapy included Salmon Calcitonin to 10 rats and Alendronate sodium to 10 rats. The bone weight of dry and ash, bone mineral density, bone biomechanical property, trabecular area, bone mineral deposition and serum alkaline phosphatase, Ca, P and urinary Pyridinoline/creatin (Pyd/Cr) were measured after the end of therapy.</p><p><b>RESULTS</b>When administered to animals as a single subcutaneous injection once daily, rhPTH(1-34) increased obviously bone mass, bone biomechanical property and trabecular area, as well as bone deposition compared with the animals of control group. The bone architecture was ultimately improved by rhPTH(1-34) therapy.</p><p><b>CONCLUSIONS</b>Rats of ovariectomized-induced osteoporosis possess obvious effect of treatment with low dose of rhPTH(1-34) administered once daily.</p>