摘要:
探讨碲化镉量子点(cadmium telluride quantum dots,CdTeQDs)Cd2+释放与其体内毒性之间的关系。将24只雄性ICR小鼠(24.7~26.8g)随机分为4组,每组6只,分别为0 nmol组(对照组)、5 nmol染毒组、50 nmol染毒组和500 nmol染毒组(以Cd2+的摩尔浓度计算)。采用尾静脉注射方式进行染毒,染毒组注射0.15 ml不同浓度的CdTeQDs溶液,对照组注射同等体积的生理盐水。染毒24h后小鼠脱臼处死,计算脏器系数,进行血常规和血清生化指标分析以及肝、肾组织的病理组织学检查。选取金属硫蛋白(metallothionein,MT)作为生物体内游离Cd2+水平的生物标志物,通过酶联免疫吸附实验(ELISA)和免疫组织化学技术检测小鼠肝、肾组织中的MT水平。结果表明,各染毒组小鼠肝、肾脏器系数与对照组相比,差异无统计学意义(P>0.05),尿素氮水平与对照组相比显著降低(P<0.01)。随着染毒剂量增加,小鼠肝、肾组织病理改变逐渐加重,肝细胞可见不同程度的水性样变和肿胀;肾小管管腔水肿、肾上皮细胞水样变性,以及远曲小管水肿。染毒组小鼠肝、肾组织中MT的含量与对照组相比明显升高(P<0.05),且随着染毒剂量增加MT表达增强。研究结果提示,CdTeQDs对小鼠肝、肾组织具有一定的毒作用,其毒作用大小与CdTeQDs降解释放的游离Cd2+含量呈正相关。
Abstract:
Hepatotoxicity and nephrotoxicity of cadmium ion (Cd2+) released from cadmium telluride quantum dots (CdTeQDs) in mice were investigated. A total of 24 ICR male mice (24.7~26.8 g) were randomly divided into four groups, and exposed to different concentrations (0, 5, 50, 500 nmol) of CdTeQDs via tail vein injection. The control group was injected with normal saline. After 24 h of the treatment, the organ coefficient and pathologi-cal changes of livers and kidneys, the serum biochemical indexes, hematologic indexes were measured. Metallothionein (MT) was selected as a biomarker of Cd2+ exposure and determined by the enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. The results showed that the blood urea nitrogen levels in serum of mice were all decreased (P<0.01) without obvious changes of the organ coefficient (P>0.05). Pathologic examination demonstrated hydropic degeneration of hepatocyte around the central vein, hepatocyte disorder, distal tubular expansion in liver and renal tubular muddy swollen, renal artery expansion hyperemia in kidneys. Compared with the control group, CdTeQDs exposed groups significantly induced the MT expression (P<0.05). Since the MT levels increased along with the exposure dosages, it suggested that the free Cd2+ might be released from CdTeQDs in liver or in kidneys. In summary, the results showed that CdTeQDs could induce toxicity and further pathologic changes of liver and kidneys, which might be positively correlated with the Cd2+ released from CdTeQDs in mice.
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