The average size of SiO2 NPs measured by TEM was 15 nm. Since nanoparticles often agglomerates in solution, the sizes of SiO2 NPs and their agglomerates in RPMI 1640 medium and physiological saline were estimated using dynamic selleck AZD9291 light scattering. The results showed that the agglomeration of SiO2 NPs was 92 nm in cell culture medium and 156 nm in physiological saline, which was nearly 6 to 10 times larger than the primary particle size. The values of the zeta potential were ?8.5 �� 1.1 mV and ?11.1 �� 1.3 mV in cell culture medium and physiological saline, respectively. Figure 1 Transmission electron microscopy image for silica nanoparticles. Effects of SiO2 NPs on KCs The ability of SiO2 NPs to induce intracellular oxidant production in KCs was assessed using 20,70-dichlorofluo rescein (DCF) fluorescence as a reporter of ROS generation.

Figure 2A shows that SiO2 NPs resulted in a dose-dependent increase in intracellular ROS in the concentration range of 100�C800 ��g/mL (P < 0.05). In addition, H2O2 in the supernatant was measured as extracellular oxidant production. As shown in Figure 2B, SiO2 NPs induced a dose-dependent release of H2O2 into the supernatant of KCs. Figure 2 Reactive oxygen species, H2O2, tumor necrosis factor-��, and nitric oxide produced by SiO2 NP-stimulated Kupffer cells. (A) Intracellular reactive oxygen species (ROS) levels of Kupffer cells (KCs) incubated with different concentrations of silica ... KCs were stimulated with SiO2 NPs for 24 hours, and secreted TNF-�� was measured in cell culture supernatants.

The ELISA results (Figure 2C) demonstrated that the secretion of TNF-�� by KCs significantly increased at the concentrations of 400 ��g/mL and 800 ��g/mL (P < 0.01). NO released into the supernatant of KCs was measured by the Griess reaction. As shown in Figure 2D, SiO2 NP-stimulated KCs produced a dose-dependent increase in NO secretion in the concentration range of 200�C800 ��g/mL (P < 0.05). KC-mediated cytotoxicity in BRL cells After coculture in the supernatant of KCs, the viability of BRL cells was determined by CCK-8. As shown in Figure 3A, the supernatants of the KCs stimulated by SiO2 NPs in the concentration range of 100�C800 ��g/mL reduced the cellular viability of BRL cells (P < 0.05). In addition, the LDH and AST levels in the culture medium of BRL cells were measured. LDH levels significantly increased when BRL cells were treated with the supernatants of SiO2 NP-stimulated KCs (Figure 3B). AST levels were enhanced only when BRL cells were exposed to the supernatants of KCs that were treated with SiO2 NPs at the concentrations of 400 ��g/mL and 800 ��g/mL (P < 0.05) (Figure 3C). Figure 3 Kupffer cell-mediated Entinostat cytotoxicity in Buffalo rat liver (BRL) cells.