Effect of Silver Nanoparticles on SRC Activity in Male Germ-line Stem Cells

摘要

Gametogenesis is a complex biological process that is particularly sensitive to environmental insults such as chemicals and physical stressors. Exposure to specific chemicals has been shown to inhibit fertility through a negative impact on germ cell proliferation and differentiation that can lower sperm count. In addition, toxicants might produce mutations that could have negative consequences on the development of the offspring. A previous study showed that a spermatogonial stem cell line, called C18-4, provides a sensitive model to assess the cytotoxicity of nanoparticles in the male germ line. We also found that Ag-15nm was more toxic than Al-30nm and MoO3-30nm for spermatogonial stem cell proliferation. The purpose of the present study was to determine the effects of various sizes of Ag nanoparticles on the C18-4 cell line using standard cytotoxic assays. We also assessed the impact of Ag nanoparticles on Src signaling, since the activation of this kinase allows normal spermatogonial stem cells to proliferate. Mitochondrial function (MTS) data showed that Ag-130nm was not toxic to the cells, but smaller particles showed toxicity. Membrane leakage was increased by treatment with the Ag-25nm and Ag-30nm particles, even at low concentrations (5 micrograms/ml). However, no membrane leakage was apparent when the cells were treated with Ag-130nm. Further, we have found that the activity of Fyn (a member of the Src family of cytoplasmic kinases) is significantly reduced when the cells are treated with Ag nanoparticles. This inhibition increases with the size of the nanoparticles, with no activity detected above a size of 30 nm.