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Updated: Jul 29, 2026
Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury
Published on: September 4, 2013
Inhibition of inflammatory mediator release from microglia can treat ischemic/hypoxic brain injury
Huaibo Wang1, Weitao Guo1, Hongliang Liu2
1Department of Orthopedics, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, Guangdong Province, China.
Abstract:
Interleukin-1α and interleukin-1β aggravate neuronal injury by mediating the inflammatory reaction following ischemic/hypoxic brain injury. It remains unclear whether interleukin-1α and interleukin-1β are released by microglia or astrocytes. This study prepared hippocampal slices that were subsequently subjected to oxygen and glucose deprivation. Hematoxylin-eosin staining verified that neurons exhibited hypoxic changes. Results of enzyme-linked immunosorbent assay found that interleukin-1α and interleukin-1β participated in this hypoxic process. Moreover, when hypoxic injury occurred in the hippocampus, the release of interleukin-1α and interleukin-1β was mediated by the P2X4 receptor and P2X7 receptor. Immunofluorescence staining revealed that during ischemia/hypoxia, the P2X4 receptor, P2X7 receptor, interleukin-1α and interleukin-1β expression was detectable in rat hippocampal microglia, but only P2X4 receptor and P2X7 receptor expression was detected in astrocytes. Results suggested that the P2X4 receptor and P2X7 receptor, respectively, mediated interleukin-1α and interleukin-1β released by microglia, resulting in hippocampal ischemic/hypoxic injury. Astrocytes were activated, but did not synthesize or release interleukin-1α and interleukin-1β.
Insights
Microglia release interleukin-1α and interleukin-1β, mediated by P2X4 and P2X7 receptors, exacerbating brain injury after hypoxia. Astrocytes are activated but do not release these inflammatory cytokines.
Area of Science:
- Neuroscience
- Neuroinflammation
- Cellular Biology
Background:
- Interleukin-1α (IL-1α) and interleukin-1β (IL-1β) worsen neuronal damage in ischemic/hypoxic brain injuries by driving inflammation.
- The specific cell types responsible for releasing IL-1α and IL-1β in the hippocampus during such injuries remain unidentified.
Purpose of the Study:
- To investigate the cellular source and receptor-mediated mechanisms of interleukin-1α and interleukin-1β release during hippocampal ischemic/hypoxic injury.
- To determine the roles of microglia and astrocytes in the inflammatory response following oxygen and glucose deprivation.
Main Methods:
- Preparation of rat hippocampal slices subjected to oxygen and glucose deprivation (OGD).
- Hematoxylin-eosin staining to assess neuronal hypoxic changes.
- Enzyme-linked immunosorbent assay (ELISA) to quantify cytokine levels.
- Immunofluorescence staining to identify the expression and localization of P2X4 receptor, P2X7 receptor, IL-1α, and IL-1β in microglia and astrocytes.
Main Results:
- OGD induced hypoxic changes in hippocampal neurons, with IL-1α and IL-1β participating in the process.
- The release of IL-1α and IL-1β during hypoxic injury was mediated by the P2X4 and P2X7 receptors.
- Immunofluorescence confirmed P2X4, P2X7, IL-1α, and IL-1β expression in microglia, while only P2X4 and P2X7 were found in astrocytes.
- Astrocytes showed activation but did not synthesize or release IL-1α or IL-1β.
Conclusions:
- Microglia are the primary source of interleukin-1α and interleukin-1β during hippocampal ischemic/hypoxic injury.
- The P2X4 and P2X7 receptors play crucial roles in mediating the release of IL-1α and IL-1β, respectively, from microglia.
- Astrocytes are involved in the inflammatory response but do not contribute to the release of these specific cytokines.
