【摘要】 目的探讨镉(Cd)对大鼠骨组织及体外培养成骨细胞中金属硫蛋白mRNA表达的影响。方法应用皮下注射的方法对Sprague-Dawley雄性大鼠进行连续Cd染毒(0～1.5 mg/kg bw)12周,5d/w,收集血样、尿样及骨组织,分别测定体内镉负荷;应用逆转录-聚合酶链反应(RT-PCR)方法检测骨组织中金属硫蛋白(MT)基因表达;同时,应用混合酶消化法分离大鼠颅盖骨成骨细胞,进行原代培养,并以不同浓度的Cd(0～2.0μmol/L)作用24 h以及1.0μmol/L Cd作用不同时间(24～72 h)后,应用RT-PCR,观察成骨细胞MT mRNA表达的变化。结果大鼠镉染毒后体内镉负荷显著增加,呈明显剂量-效应关系;镉染毒能够诱导大鼠骨组织MT基因表达,各剂量染毒大鼠骨组织MT基因表达均明显高于对照组,P<0.05。体外实验结果同样表明,镉作用能诱导成骨细胞MT表达,并随着染镉剂量的增加,MT基因表达也明显增高,特别是在0.5μmol/L和2.0μmol/L组,和对照组相比差异有显著意义(P<0.01);1.0μmol/L CdCl2作用不同时间后均能诱导成骨细胞MT表达,但表达量并不随镉作用时间而出现明显改变。结论镉能诱导骨组织及体外培养成骨细胞MT表达,MT可能镉在致骨损伤中有一定保护作用。更多还原

【Abstract】 Objective To investigate the effect of cadmium(Cd) on metallothionein(MT) mRNA expression in the bone tissue and in osteoblasts in rats.Methods Sprague-Dawley(SD) male rats were injected with Cd subcutaneously at the doses of 0,0.1,0.5,and 1.5 mg/kg,5 times per week,for 12 weeks.Blood,24h urine,and bone tissue were collected for examining Cd loading.MT mRNA expression in the bone was determined using reverse transcription polymerase chain reaction(RT-PCR).Meanwhile,osteoblasts were harvested from the rat calvaria using sequential enzyme digestion method.Cells were cultured and treated with different concentrations of Cd(0-2.0 μmol/L) for 24h or different times(24-72 h) at 1.0μmol/L.MT mRNA expression in osteoblasts was determined using RT-PCR.Results The Cd concentration in the rat was significantly increased after Cd loading.The increase was dose-dependent.Cd injection induced MT expression in the bone tissue.MT expression in rats with Cd injection of all doses was significantly higher than that in the control(P<0.05).In vitro experiment demonstrated that Cd induced MT expression in osteoblasts.The increase of MT expression was dose-dependent,especially at dose of 0.5 and 2.0 μmol/L of Cd(P<0.01).The increase was significantly different compared with the control.Cd(1.0μmol/L) induced MT expression in osteoblasts,but the expression level was not time-dependent.Conclusion Cd could induce MT expression in the bone tissue and in cultured osteoblasts in vitro.MT may更多还原