Lab Anim Res.  2017 Sep;33(3):244-250. 10.5625/lar.2017.33.3.244.

Cerebral ischemic injury decreases α-synuclein expression in brain tissue and glutamate-exposed HT22 cells

• Koh PO

• KMID: 2391098
• DOI: http://doi.org/10.5625/lar.2017.33.3.244

Abstract

α-Synuclein is abundantly expressed in neuronal tissue, plays an essential role in the pathogenesis of neurodegenerative disorders, and exerts a neuroprotective effect against oxidative stress. Cerebral ischemia causes severe neurological disorders and neuronal dysfunction. In this study, we examined α-synuclein expression in middle cerebral artery occlusion (MCAO)-induced cerebral ischemic injury and neuronal cells damaged by glutamate treatment. MCAO surgical operation was performed on male Sprague-Dawley rats, and brain samples were isolated 24 hours after MCAO. We confirmed neurological behavior deficit, infarction area, and histopathological changes following MCAO injury. A proteomic approach and Western blot analysis demonstrated a decrease in α-synuclein in the cerebral cortices after MCAO injury. Moreover, glutamate treatment induced neuronal cell death and decreased α-synuclein expression in a hippocampal-derived cell line in a dose-dependent manner. It is known that α-synuclein regulates neuronal survival, and low levels of α-synuclein expression result in cytotoxicity. Thus, these results suggest that cerebral ischemic injury leads to a reduction in α-synuclein and consequently causes serious brain damage.

Keyword

α-synuclein; cerebral ischemia; hippocampal-derived cell line; MCAO

MeSH Terms

Blotting, Western
Brain Ischemia
Brain*
Cell Death
Cell Line
Cerebral Cortex
Glutamic Acid
Humans
Infarction
Infarction, Middle Cerebral Artery
Male
Nervous System Diseases
Neurodegenerative Diseases
Neurons
Neuroprotective Agents
Oxidative Stress
Rats, Sprague-Dawley
Glutamic Acid
Neuroprotective Agents

Figure

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  Figure 1 Neurobehavioral scores (A), photographs of TTC staining (B), infarct volume (C), and histopathological changes (D) in the cerebral cortex of sham-operated and middle cerebral artery occlusion (MCAO)-operated animals. The intact area appears red, while the ischemic area appears white (B). The percentage of ischemic lesion area was calculated by the ratio of the infarction area to the area of the entire section (C). Arrows indicate neuronal cells with a shrunken and swollen shape (D). Data (n=5) are shown as mean±SEM. *P<0.01 vs. sham animals. Scale bar = 100 µm.

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  Figure 2 Image showing the proteomic approach (A) and Western blot analysis (B) of α-synuclein in the cerebral cortex from sham-operated and middle cerebral artery occlusion (MCAO)-operated animals. Circles indicate α-synuclein protein spots. Spot intensities were measured by PDQuest software. The spot intensities are reported as a ratio relative to the sham-operated animals as a control (C). Each lane represents an individual animal. Densitometric analysis is represented as a ratio of α-synuclein protein intensity to actin protein intensity (D). Data (n=5) are shown as mean±SEM. *P<0.05 vs. sham animals.

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  Figure 3 Cell viability (A) and Western blot analysis of α-synuclein in HT22 cells (B). Cellular viability was assessed using the MTT assay. Cell survival was expressed as a percentage of neuroprotection vs. vehicle (glutamate 0 mM) set at 1 (A). Densitometric analysis is represented as the intensity of α-synuclein to intensity of actin (C). Data (n=5) are expressed as mean±SEM. *P<0.05 vs. vehicle, **P<0.01 vs. vehicle.

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