镉是危害人体健康的环境污染物，近年来由于其职业暴露和环境污染逐渐加重而益发引起高度关注。胎盘是镉蓄积的靶器官之一，与铅、汞等重金属的通透性不同，胎盘对镉具有明显的屏障作用，富含半胱氨酸残基蛋白与屏障作用密切相关，但有关作用方式和机制不明。为明确富含半胱氨酸残基蛋白介导胎盘对镉屏障作用的机制，本研究通过模拟职业人群的实际暴露水平，采用镉富集稳定同位素示踪技术，建立低剂量镉暴露的动物模型，利用蛋白质组学技术定量分析胎盘的富含半胱氨酸残基蛋白，筛选镉暴露胎盘屏障作用的关键靶蛋白，蛋白印迹确认，免疫组化定位，体外细胞染毒研究其功能，并进一步在镉暴露人群中加以验证。本研究将揭示胎盘对镉暴露屏障作用的关键靶蛋白，确定其在胎盘组织的具体定位，阐明其与屏障作用的机制关系，为镉暴露早期监测生物标志物的基础研究提供依据。

Cadmium, harmful to human health, is highly paid attention because of its occupational exposure and environment pollution. Although placenta is one of the target organs of cadmium, it has obvious effect of placenta barrier effect blocking cadmium entering the embryo, which is quite different from lead and mercury. Some evidences suggest that enrich cysteine residue protein plays an important role in cadmium placenta barrier, but the molecular mechanism of the protein remains to be elucidated. To detect the mechanisms of enrich cysteine residue protein mediating the cadmium placenta barrier, we are to establish a low-cadmium exposure animal model with enriched stable isotope 112Cd by imitating the level of occupational cadmium exposure. Enrich cysteine residue protein in placenta is quantificationally analyzed with technics of proteomics. Key proteins affecting the functions of placenta barrier are to be screened and confirmed with western blotting and immunohistochemistry. On the other hand, the functions of these key proteins are to be studied in the cells exposed the different doses of cadmium.Finally, candidate protein as a biomarker will be validated in cadmium-exposed workers in epidemiological investigation. This study will reveal the key target proteins after low level cadmium exposure and understand their roles in the placental barrier, as well as their relationships with secondary adverse effects in cadmium reproductive toxicity. Furthermore, this study also provides the basis to develop the enrich cysteine residue protein as sensitive biomarkers for cadmium exposure.