Microglial cells (BV-2) internalize titanium dioxide (TiO2) nanoparticles: toxicity and cellular responses

Area of Science:

• Nanotechnology
• Toxicology
• Neuroscience

Background:

• Titanium dioxide nanoparticles (TiO2-NPs) possess whitening and photocatalytic properties, leading to their widespread use in consumer products.
• The biological impact of TiO2-NPs, particularly on the central nervous system, remains incompletely understood.
• The brain is recognized as a potential target organ for TiO2-NP toxicity.

Purpose of the Study:

• To investigate the effects of varying TiO2-NP concentrations on murine microglial cells (BV-2).
• To assess TiO2-NP impact on cell viability, growth, and neurotoxicity.
• To evaluate specific cellular responses including mitochondrial function and oxidative stress.

Main Methods:

• Exposure of BV-2 cells to TiO2-NPs (0.1–200 μg/mL).
• Measurement of cell viability, proliferation, DNA content (SubG1 peak), mitochondrial depolarization, and reactive oxygen species (ROS) production.
• Ultrastructural analysis using microscopy.

Main Results:

• TiO2-NPs exhibited cytotoxic effects, including inhibition of cell adhesion and growth at higher concentrations.
• Increased cytoplasmic membrane permeability and loss of mitochondrial transmembrane potential were observed.
• Significant overproduction of superoxide anions and mitochondrial dysfunction were noted, but no apoptosis was induced.
• Microscopic analysis revealed BV-2 cells engulfing TiO2-NPs, forming intracytoplasmic aggregates.

Conclusions:

• Accumulation of TiO2-NPs in microglial cells leads to mitochondrial dysfunction.
• Oxidative stress is a key mechanism in TiO2-NP-induced neurotoxicity in microglial cells.
• While not inducing apoptosis, TiO2-NPs exert cytotoxic effects impacting cell health and function.