Various studies in rodents have shown that nanoparticles are transferred to the breast milk. Under the present study, lactating Wistar rats were repetitively gavaged 5, 25, and 50 mg/kg bw of zinc oxide nanoparticles (ZnO-NPs) and 50 mg kg-1 bw of bulk zinc oxide (bZnO) for 19 days after parturition. The results showed that ZnO-NPs were absorbed in the small intestine of dams and distributed to the liver. Furthermore, ZnO-NPs were distributed to the intestine and liver of rat pups through dam's milk. No significant change in body weight was observed in the dams treated with ZnO-NPs or bZnO and their offsprings as compared to the control group. The spleen weight significantly increased in the rat dams treated with 50 mg kg-1 of ZnO-NPs. ZnO-NPs were mostly excreted through feces. The levels of liver cytochrome P450 reductase and serum total antioxidant capacity significantly decreased in the rat dams treated with ZnO-NPs (50 mg kg-1) and their offsprings. The levels of serum cytokines (tumor necrosis factor-alpha and interleukin-1 beta) and liver injury marker enzymes (alanine aminotransferase and aspartate aminotransferase) significantly increased in the rat dams treated with ZnO-NPs (25 and 50 mg kg-1) and their offsprings. The level of immunoglobulin A secretion in the intestinal fluid of rat dams and their offsprings is significantly increased by increasing the dose of ZnO-NPs. Histopathology of intestine and liver of offsprings whose rat dams were treated with ZnO-NPs (50 mg kg-1) showed gross pathological changes. These results provide information for the safety evaluation of ZnO-NPs use during lactation. In conclusion, a dose-dependent postnatal transfer of ZnO-NPs is hazardous to the breastfed offsprings.

中文翻译：

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通过口服途径将ZnO纳米粒子产后分布到母乳中，并对母乳喂养的后代进行风险评估。

在啮齿动物中的各种研究表明，纳米颗粒被转移到母乳中。在本研究中，分娩后，对哺乳的Wistar大鼠重复灌胃5、25和50 mg / kg bw的氧化锌纳米颗粒（ZnO-NPs）和50 mg kg-1 bw的散装氧化锌（bZnO），持续19天。结果表明，ZnO-NPs在大坝的小肠中被吸收并分布到肝脏。此外，ZnO-NPs通过大坝的牛奶分配到幼鼠的肠和肝。与对照组相比，在用ZnO-NPs或bZnO处理的大坝及其后代中没有观察到体重的显着变化。在用50 mg kg-1的ZnO-NPs处理的大鼠大坝中，脾脏重量显着增加。ZnO-NPs主要通过粪便排出。在用ZnO-NPs（50 mg kg-1）处理的大鼠及其后代中，肝细胞色素P450还原酶的水平和血清总抗氧化能力显着降低。在用ZnO-NPs（25和50 mg kg-1）处理的大鼠大坝中，血清细胞因子（肿瘤坏死因子-α和白介素-1β）和肝损伤标记酶（丙氨酸氨基转移酶和天冬氨酸氨基转移酶）的水平显着增加，并且他们的后代。通过增加ZnO-NPs的剂量，大鼠大坝及其后代的肠液中免疫球蛋白A的分泌水平显着增加。用ZnO-NPs（50 mg kg-1）处理大鼠大坝后代的肠和肝脏的组织病理学表现出明显的病理变化。这些结果为哺乳期间使用ZnO-NPs的安全性评估提供了信息。