Objective: To investigate the reproductive toxicity of cadmium sulfide nanoparticles (Nano-CdS) with different particle sizes on male mice. Methods: In January 2019, 30 SPF grade male mice were randomly divided into a control group, an experimental group[CdS Ⅰ group (particle size approximately 5 nm), and a CdS Ⅱ group (particle size approximately 50 nm) ], with 10 mice in each group. The experimental group was orally gavaged with 100 mg/kg, once a day, while the control group was gavaged with an equal volume of physiological saline for 45 consecutive days. After 45 days, levels of cadmium accumulation in testis were determined directly by AAS, deformity and testicular histopathological changes were also observed. Serum testosterone levels were measured by enzyme-linked immunosorbentassay (ELISA), expression levels of P450scc, 17β-HSD and P450c17 mRNA were determined by real-time PCR. P450c17 protein was determinated by Western Blot. Results: The histopathological results showed that the testes of the experimental group mice showed varying degrees of damage; Ultrastructural observation showed that the ultrastructure of mouse testicular cells in each experimental group showed varying degrees of mitochondrial expansion and disappearance of cristae, as well as irregular nuclear membranes. The degree of damage in CdS Ⅰ group was milder than that in CdS Ⅱ group. Compared with the control group, the cadmium content in the testes of the CdS Ⅰ and CdS Ⅱ groups significantly increased (P=0.001, 0.001), and the CdS Ⅱ group was higher than the CdS Ⅰ group (P=0.001). Compared with the control group, the levels of testosterone in the CdS Ⅰ and CdS Ⅱ groups decreased with statistical significance (P=0.001, 0.001). Real time fluorescence quantitative PCR results showed that compared with the control group, the experimental group's P450scc, 17β-HSD. The expression levels of 17β-HSD and P450c17 mRNA were significantly reduced, with statistically significant differences (P=0.001, 0.001, 0.001), and CdS Ⅱ group 17β-HSD. The expression levels of 17β-HSD and P450c17 mRNA were significantly lower than those of CdS Ⅰ group (P=0.001, 0.036). The Western Blot assay results showed that the expression levels of P450c17 protein in the testes of CdS Ⅰ and CdS Ⅱ groups of mice were significantly reduced, with statistical significance (P=0.001, 0.001) ; And the CdS Ⅱ group was significantly lower than the CdS Ⅰ group (P=0.001). According to Spearman correlation analysis, testosterone levels are correlated with P450scc, P450c17, 17β-HSD mRNA. There is a highly positive correlation between 17β-HSD mRNA levels, with statistically significant differences (r(s)=0.88, 0.80, 0.70, P=0.001, 0.001, 0.004) . Conclusion: Nano cadmium sulfide may induce reproductive toxicity by reducing the expression levels of key enzyme genes and enzyme protein activity in testosterone and its synthesis in mice, and the CdS Ⅱ group has a stronger toxic effect.
目的： 探讨不同粒径的纳米硫化镉（Nano-CdS）对雄性小鼠的生殖毒性。 方法： 于2019年1月，将30只SPF级雄性小鼠随机分为对照组、实验组[CdS I组（粒径约5 nm）和CdS Ⅱ组（粒径约50 nm）]，每组10只。实验组经口灌胃100 mg/kg Nano-CdS，1次/d，对照组灌胃等体积生理盐水，连续45 d。观察小鼠睾丸组织的病理学变化，使用透射显微镜观察睾丸组织中细胞核、线粒体等细胞器的超微结构，采用石墨炉原子吸收光谱法（AAS）检测睾丸组织中镉元素富集水平，采用ELISA试剂盒测定血清中睾酮激素水平，采用实时荧光定量PCR检测睾丸组织中基因细胞色素P450胆固醇侧链裂解酶（P450scc）、17α-羟化酶（P450c17）、17β羟基类固醇脱氢酶（17β-HSD）mRNA表达水平。采用Western Blot测定P450c17蛋白的表达水平。 结果： 组织病理学结果显示实验组小鼠睾丸均出现不同程度损伤；超微结构观察显示各实验组的小鼠睾丸细胞的超微结构均不同程度线粒体膨胀和嵴消失，核膜的不规则，CdS Ⅰ组损伤程度轻于CdSⅡ组。与对照组比较，CdS Ⅰ组和CdS Ⅱ组小鼠血清睾丸镉元素含量明显增加（P=0.001、0.001），CdSⅡ组高于CdSⅠ组（P=0.001）。与对照组比较，CdS Ⅰ组和CdSⅡ组小鼠血清睾酮水平降低，差异有统计学意义（P=0.001、0.001）。实时荧光定量PCR结果显示：与对照组比较，实验组的P450scc、P450c17 mRNA表达水平明显降低，差异有统计学意义（均P<0.05），CdSⅡ组17β-HSD mRNA表达水平降低（P=0.001）；且CdSⅡ组17β-HSD、P450c17 mRNA表达水平明显低于CdSⅠ组（P=0.001、0.036）。Western Blot测定结果显示：CdSⅠ组和CdSⅡ组小鼠睾丸中P450c17蛋白表达水平明显降低，差异有统计学意义（P=0.001、0.001）；且CdS Ⅱ组明显低于CdS Ⅰ组（P=0.001）。经Spearman相关分析，睾酮水平与P450scc、P450c17、17β-HSD mRNA水平之间呈正相关，差异有统计学意义（r(s)=0.88、0.80、0.70，P=0.001、0.001、0.004）。 结论： 纳米硫化镉可能通过降低小鼠的睾酮及其合成关键酶基因表达水平及酶蛋白活性从而产生生殖毒性，且CdS Ⅱ组毒性作用更强。.
Keywords: 17α-hydroxylation; 17β-hydroxysteroid dehydrogenase; Cadmium sulfide; Cholesterol side-chain cleavage enzyme; Nano; Nanoparticle size; Reproductive toxicity; Testosterone.