Evaluation On The Toxicology Of Silver Nanoparticles By Endoplasmic Reticulum Stress Respone In Cell And Mouse Model

Part 1: Objective: This study was designed to investigate the toxicity of silver nanoparticles(Ag NPs) on mice macrop hage cell line RAW264.7 in order to provide the data for understanding their biosafety. Methods: Cell viability was determined by the MTT method in RAW264.7 cells after incubation with a number concentrations of Ag NPs(0, 6.25, 12.5, 25, 50, 60, 80 μg/m L). The doses of 2.5 μg/m L and 5 μg/m L, which did not cause significant cytotoxicity to RAW264.7 cells, were used for the following cell treatments to observe the cellular morphology and to determine the protein expression of the stress-related biomarkers. The levels of TNF-α and IL-6 in the cultural media were determined with ELISA. Results: When the RAW264.7 cells were treated with the 2.5 μg/m L and 5 μg/m L of Ag NPs for 24 h, the Ag NPs were found to be internalized into the cells and significant changes of cellular morphology were also observed in the 5 μg/m L groups. There were not clear alternation in the expression of IL-6 in the groups treated with Ag NPs for 8 and 24 h, but there was increased expression of TNF-α observed in the groups treated with Ag NPs for 24 h. Further, the endoplasmic reticulum stress response makers and oxidative-stress proteins were also found to be significantly upregulated in RAW264.7 cells treated with 5 μg/m L of Ag NPs for 24 h. Conclusion: There are obviously adverse effects of low dose of nano-silver exposure on RAW264.7 cells and clearly positive relationship between the effects and the doses and time of Ag NPs exposure. One of the necessary factors by which the cytotoxicities were caused is that the Ag NPs should be internalized into the RAW264.7 cells. These results suggested that exposure to Ag NPs, even at the relatively lower doses, may disturb the normal cellular physiological functions. Great concerns should be taken on the irreversible damage of the long-termed Ag NPs exposure to the cells in the future.Part 2: Objective: Study on the principal target organ and toxic effects after Ag NPs intravenous injection, to assess the toxic effects of Ag NPs on human health and the environment. Methods: In this paper we checked the organ toxicity of mouse after intravenous administration of Ag NPs at a single-dose of 0.2, 2 or 5 mg/kg(B/W). Biodistribution, endoplasmic reticulum stress, oxidative stress were examined in organs of animals at eight hours after exposure. Results: Stress marker proteins/genes were significantly upregulated at a dose-dependent manner. Acute toxic formed accompanied with the highest stress happens in liver, spleen, lung and kidney. We propose these organs are dominant target organs of Ag NPs toxicity. While there were low stress/toxicity formed in heart and brain may from the reason that there were low quantities of Ag NPs distributed in these two organs. Conclusion: Our results demonstrated Ag NPs leading to permanent toxic damage through gradually imposing stress impacts in target organs. These findings highlight the applications of stress markers in future risk evaluation of silver nanoparticle with intention to avoiding its reality damages.