Cytotoxicity and immunomodulatory effects of sol-gel combustion based titanium dioxide (TiO2) particles of large surface area on RAW 264.7 macrophages

• Published in: Toxicology in vitro 2017-09, Vol.43, p.92-103
• Main Authors: Dinesh, Palani, Suresh Yadav, C., Kannadasan, Sathanandhan, Rasool, Mahaboobkhan
• Format: Article
• Language: English
• Subjects: Alanine; Alanine - chemistry; Amino acids; Animals; Cell Survival - drug effects; Chemical synthesis; Combustion; Cyclooxygenase-2; Cytokines; Cytokines - genetics; Cytokines - metabolism; Cytotoxicity; Gene expression; Glycine; Glycine - chemistry; Immune response; Immunology; Immunomodulation; Inflammation; Inflammatory mediators; Interleukin 6; Intracellular; L-Alanine; L-Lactate Dehydrogenase - metabolism; Lipopolysaccharides; Macrophages; Macrophages - drug effects; Macrophages - metabolism; Mice; NF-κB protein; Nitric-oxide synthase; Particulates; RAW 264.7 Cells; Reactive oxygen species; Reactive Oxygen Species - metabolism; Reducing agents; RNA, Messenger - metabolism; Sol-gel combustion method; Sol-gel processes; Surface area; Surface Properties; TiO2 particles; Titanium; Titanium - chemistry; Titanium - toxicity; Titanium dioxide; Toxicity; Tumor necrosis factor-α
• ISSN: 0887-2333; 1879-3177
• DOI: 10.1016/j.tiv.2017.06.006

The current study was designed to investigate the cytotoxicity and immunomodulatory effects of sol-gel combustion based TiO2 particles (glycine and l-alanine as reducing agents) of large surface area on RAW 264.7 macrophages. RAW 264.7 macrophages exposed to varying concentrations of TiO2 particles (0.001 to 1000μg/ml) were assessed after 24h and showed a reduced cell viability at 100 and 1000μg/ml and increased LDH release at 10μg/ml. Furthermore, TiO2 particles (0.1, 1 and 10μg/ml) were utilized to assess the immune responses and intracellular ROS levels on RAW 264.7 macrophages. TiO2 particles at 10μg/ml showed increased mRNA expression of inflammatory cytokines (TNFα, IL-1β and IL-6), inflammatory mediators (iNOS and COX-2) and transcription factor (NFκB) similar to that of LPS stimulated macrophages. However, the mRNA expression levels were found near normal levels at lower concentrations (0.1 and 1μg/ml). In addition, TiO2 particles at 10μg/ml also increased the production of inflammatory cytokines (TNFα, IL-1β and IL-6) and intracellular ROS levels in RAW 264.7 macrophages similar to that of LPS stimulated macrophages. Conclusively, TiO2 particles prepared through this method at a concentration≤0.1μg/ml can be used for various biological applications with minimal immunomodulatory effects. [Display omitted] •Sol-gel combustion based TiO2 particles (glycine and l-alanine as reducing agents).•In vitro cytotoxicity analysis of TiO2 particles of large surface area.•Immune responses of low concentrations of TiO2 particles.•ROS levels of cells exposed to TiO2 particles.