Related Experiment Video
Updated: May 24, 2026
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
[Effect of hyperoxia exposure on the function of N9 microglia in vitro]
Pu Jiang1, Ying Xu, Liangan Hu
1Department of Forensic Medicine, Chongqing Medical University, Chongqing, China. jiangpu_e@163.com
Objective:
To observe the effect of normobaric hyperoxia exposure on the functions of N9 microglia and explore the underlying mechanism of hyperoxia-induced immature brain injury.
Methods:
N9 microglial cells were exposed to 900 ml/L O(2) for 2, 6, 12, 24 or 48 h, and the cell apoptotic rate was assessed using flow cytometry. The intracellular oxidative stress was measured using a fluorescent DCFH-DA probe, and the expression of Toll-like receptor 4 (TLR4) mRNA was detected using RT-PCR. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) concentrations in the supernatant of the cell cultures were tested with ELISA following the exposures. TLR4 protein expression was observed using immunofluorescence staining.
Results:
Significant cell apoptosis was detected after oxygen exposures for 12-24 h. Accumulation of reactive oxygen species (ROS) were detected after a 2-h exposure. After prolonged hyperoxia exposure, TLR4 expression and IL-1β and TNF-α levels significantly increased in the cells.
Conclusion:
Hyperoxia exposure activates TLR4 signaling pathway in N9 microglial cells in vitro, leading to massive production of ROS, IL-1β, and TNF-α and thus triggering cell apoptosis.
Insights
Normobaric hyperoxia exposure triggers N9 microglial cell apoptosis by activating the Toll-like receptor 4 (TLR4) pathway. This leads to increased reactive oxygen species (ROS), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) production.
Area of Science:
- Neuroscience
- Immunology
- Cell Biology
Context:
- Immature brain injury is a significant concern.
- Microglia play a critical role in neuroinflammation.
- Normobaric hyperoxia is a potential contributing factor to brain injury.
Purpose:
- To investigate the impact of normobaric hyperoxia on N9 microglial cell function.
- To elucidate the mechanisms underlying hyperoxia-induced immature brain injury.
Summary:
- N9 microglial cells exposed to hyperoxia showed increased apoptosis after 12-24 hours.
- Reactive oxygen species (ROS) accumulated within 2 hours of exposure.
- Toll-like receptor 4 (TLR4) expression, along with IL-1β and TNF-α levels, significantly increased following prolonged hyperoxia.
Impact:
- Hyperoxia exposure activates the TLR4 signaling pathway in microglia.
- This activation results in elevated ROS, IL-1β, and TNF-α production.
- The study demonstrates a mechanism for hyperoxia-induced microglial cell apoptosis.
