Recovery of focal brain ischemia-induced behavioral dysfunction by intracerebroventricular injection of microglia
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Updated: Aug 19, 2026
Isolation and Flow Cytometric Assessment of Neuroimmune Interactions in a Mini-Stroke Murine Model
Published on: June 20, 2025
Yoshihisa Kitamura1, Daijiro Yanagisawa, Masatoshi Inden
1Department of Neurobiology, Kyoto Pharmaceutical University, Japan. yo-kita@mb-kyoto-phu.ac.jp
Abstract:
The function of microglia in the brain parenchyma is not fully understood. Occlusion of the middle cerebral artery (MCA) and reperfusion caused behavioral dysfunction with massive neuronal loss in the rat cerebral cortex and striatum. When exogenous microglia were microinjected into the intracerebroventricle (i.c.v.) during MCA occlusion, focal ischemia-induced behavioral dysfunction was significantly inhibited. At that time, many microglia migrated into the ischemic lesion, and microglia-derived neuron-like cells were barely detectable. These results suggest that exogenous microglia protect against focal ischemia-induced neurodegeneration and improve behavioral dysfunction.
Insights
Introducing exogenous microglia into the brain significantly reduced behavioral deficits and neuronal loss following middle cerebral artery occlusion (MCA) stroke in rats. These findings highlight microglia's protective role in focal cerebral ischemia.
Area of Science:
- Neuroscience
- Immunology
- Stroke Research
Background:
- The precise role of microglia, the brain's resident immune cells, within the brain parenchyma remains incompletely elucidated.
- Focal cerebral ischemia, induced by middle cerebral artery (MCA) occlusion and subsequent reperfusion, leads to significant behavioral impairments and widespread neuronal death in the cerebral cortex and striatum.
Purpose of the Study:
- To investigate the neuroprotective potential of exogenous microglia in a rat model of focal cerebral ischemia.
- To determine if microinjection of microglia can mitigate the functional and histological consequences of MCA occlusion.
Main Methods:
- Rats underwent middle cerebral artery occlusion (MCAO) to induce focal cerebral ischemia.
- Exogenous microglia were administered via microinjection into the intracerebroventricle (i.c.v.) during the ischemic period.
- Behavioral tests were conducted to assess functional deficits.
- Histological analysis examined neuronal loss in the affected brain regions.
Main Results:
- Microinjection of exogenous microglia significantly inhibited the development of behavioral dysfunction caused by focal ischemia.
- A substantial migration of these exogenous microglia into the ischemic lesion was observed.
- The formation of microglia-derived neuron-like cells was minimal within the observed timeframe.
Conclusions:
- Exogenous microglia demonstrate a protective effect against neurodegeneration in focal cerebral ischemia.
- Administration of microglia can ameliorate behavioral deficits associated with stroke.
- These findings suggest a therapeutic potential for microglia-based strategies in treating ischemic stroke.
