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Characteristic Changes of Astrocyte and Microglia in Rat Striatum Induced by 3-NP and MCAO
Shuhua Mu1, Bingbing Liu2, Lisi Ouyang3
1Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China.
Abstract:
Our previous studies had confirmed that both 3-NP and MCAO induced the behavioral defect as well as striatal neuronal injury and loss in experimental rats. This study aimed to examine different response forms of striatal astrocyte and microglia in 3-NP and MCAO rat models. The present results showed that the immunoreaction for GFAP was extremely weak in the lesioned core of striatum, but in the transition zone of 3-NP model and the penumbra zone of MCAO model, GFAP+ cells showed strong hypertrophic and proliferative changes. Statistical analysis for the number, size and integral optical density (IOD) of GFAP+ cells showed significant differences when compared with their controls and compared between the core and the transition zone or the penumbra zone, respectively, but no differences between the 3-NP and MCAO groups. However, Iba-1+ cells showed obvious hypertrophy and proliferation in the injured striatum in the 3-NP and the MCAO models, especially in the transition zone of 3-NP model and the penumbra zone of MCAO model. These Iba-1+ cells displayed two characteristic forms as branching cells with thick processes and amoeboid cells with thin processes. Statistical analysis showed that the number, size and IOD of Iba-1+ cells were significantly increased in the cores and the transition zone of 3-NP group and the penumbra zone of MCAO group than that of the controls, and the immune response of Iba-1 was stronger in the MCAO group than in the 3-NP group. The present results suggested that characteristic responses of astrocyte and microglia in the 3-NP and the MCAO models display their different effects on the pathological process of brain injury.
Insights
This study reveals distinct astrocyte and microglia responses in rat models of brain injury. While both cell types show changes, microglia exhibit a stronger immune response in the MCAO model compared to the 3-NP model.
Area of Science:
- Neuroscience
- Cell Biology
- Pathology
Background:
- Previous studies confirmed 3-nitropropionic acid (3-NP) and middle cerebral artery occlusion (MCAO) induce behavioral defects and striatal neuronal injury in rats.
- Astrocytes and microglia are key glial cells involved in neuroinflammation and brain injury response.
Purpose of the Study:
- To investigate and compare the distinct response patterns of striatal astrocytes and microglia in 3-NP and MCAO-induced rat models of brain injury.
- To analyze the morphological and quantitative changes in these glial cells within different injury zones.
Main Methods:
- Utilized 3-NP and MCAO rat models to induce experimental brain injury.
- Performed immunohistochemical analysis for glial fibrillary acidic protein (GFAP) in astrocytes and ionized calcium-binding adapter molecule 1 (Iba-1) in microglia.
- Quantitatively analyzed cell number, size, and integral optical density (IOD) in different striatal regions (core, transition, penumbra).
Main Results:
- GFAP+ astrocyte reactivity (hypertrophy, proliferation) was observed in the transition zone (3-NP) and penumbra (MCAO), but weak in the core.
- Iba-1+ microglia showed significant hypertrophy and proliferation in injured striata, with two distinct forms (branching and amoeboid).
- Microglial response (number, size, IOD) was significantly increased in both models, with a stronger immune response noted in the MCAO group compared to the 3-NP group.
Conclusions:
- Astrocytes and microglia exhibit differential responses in 3-NP and MCAO models, influencing the pathological processes of brain injury.
- The distinct cellular responses highlight the complex neuroinflammatory mechanisms underlying different types of brain insults.
- Understanding these glial cell dynamics is crucial for developing targeted therapeutic strategies for neurodegenerative diseases and stroke.
