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Protective Effect of Edaravone on Glutamate-Induced Neurotoxicity in Spiral Ganglion Neurons

View Article: PubMed Central - PubMed

ABSTRACT

Glutamate is an important excitatory neurotransmitter in mammalian brains, but excessive amount of glutamate can cause “excitotoxicity” and lead to neuronal death. As bipolar neurons, spiral ganglion neurons (SGNs) function as a “bridge” in transmitting auditory information from the ear to the brain and can be damaged by excessive glutamate which results in sensorineural hearing loss. In this study, edaravone, a free radical scavenger, elicited both preventative and therapeutic effects on SGNs against glutamate-induced cell damage that was tested by MTT assay and trypan blue staining. Ho.33342 and PI double staining revealed that apoptosis as well as necrosis took place during glutamate treatment, and apoptosis was the main type of cell death. Oxidative stress played an important role in glutamate-induced cell damage but pretreatment with edaravone alleviated cell death. Results of western blot demonstrated that mechanisms underlying the toxicity of glutamate and the protection of edaravone were related to the PI3K pathway and Bcl-2 protein family.

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Treatment of edaravone buffered the toxicity of glutamate towards SGNs. Cell viability was detected by MTT assay (a) and trypan blue staining (b). Three groups were treated with 500 μM edaravone 2 h, 6 h, and 12 h after administration of glutamate, respectively. ∗p < 0.05, versus glutamate-treated group. The data shown here was the mean ± SEM of three separate experiments.
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fig5: Treatment of edaravone buffered the toxicity of glutamate towards SGNs. Cell viability was detected by MTT assay (a) and trypan blue staining (b). Three groups were treated with 500 μM edaravone 2 h, 6 h, and 12 h after administration of glutamate, respectively. ∗p < 0.05, versus glutamate-treated group. The data shown here was the mean ± SEM of three separate experiments.

Mentions: In order to estimate the protective effect of edaravone, MTT assay and trypan blue staining were performed to measure cell viability. The cell viability of control group was considered as 100%. Figure 4 showed that one group of SGNs was treated with glutamate alone, while the other three groups were pretreated with edaravone at different concentrations (250 μM, 500 μM, and 750 μM) for 20 min before glutamate treatment. The cell viabilities of MTT test were 32%, 48%, 75%, and 78% for each group, respectively (Figure 4(a)), and those of trypan blue staining were 30%, 45%, 72%, and 70% (Figure 4(b)). These results revealed that pretreatment with edaravone increased the cell viability of SGNs and the protective effect was presented in a dose-dependent manner. The protection reached the peak at the concentration of 500 μM and no obvious benefits were observed by further elevating the concentration. Figure 5 showed that one group of SGNs was treated with glutamate alone, while the other three were treated with 500 μM edaravone 2 h, 6 h, or 12 h after glutamate treatment, respectively. The cell viabilities of MTT test were 25%, 49%, 35%, and 33%, respectively (Figure 5(a)), and those of trypan blue staining were 22%, 40%, 32%, and 30% (Figure 5(b)). Treatment of edaravone at the time point of 2 h after glutamate achieved satisfying protection for SGNs against glutamate-induced cytotoxicity. But there was no significant improvement in cell viability when treated at later time points.


Protective Effect of Edaravone on Glutamate-Induced Neurotoxicity in Spiral Ganglion Neurons
Treatment of edaravone buffered the toxicity of glutamate towards SGNs. Cell viability was detected by MTT assay (a) and trypan blue staining (b). Three groups were treated with 500 μM edaravone 2 h, 6 h, and 12 h after administration of glutamate, respectively. ∗p < 0.05, versus glutamate-treated group. The data shown here was the mean ± SEM of three separate experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5121579&req=5

fig5: Treatment of edaravone buffered the toxicity of glutamate towards SGNs. Cell viability was detected by MTT assay (a) and trypan blue staining (b). Three groups were treated with 500 μM edaravone 2 h, 6 h, and 12 h after administration of glutamate, respectively. ∗p < 0.05, versus glutamate-treated group. The data shown here was the mean ± SEM of three separate experiments.
Mentions: In order to estimate the protective effect of edaravone, MTT assay and trypan blue staining were performed to measure cell viability. The cell viability of control group was considered as 100%. Figure 4 showed that one group of SGNs was treated with glutamate alone, while the other three groups were pretreated with edaravone at different concentrations (250 μM, 500 μM, and 750 μM) for 20 min before glutamate treatment. The cell viabilities of MTT test were 32%, 48%, 75%, and 78% for each group, respectively (Figure 4(a)), and those of trypan blue staining were 30%, 45%, 72%, and 70% (Figure 4(b)). These results revealed that pretreatment with edaravone increased the cell viability of SGNs and the protective effect was presented in a dose-dependent manner. The protection reached the peak at the concentration of 500 μM and no obvious benefits were observed by further elevating the concentration. Figure 5 showed that one group of SGNs was treated with glutamate alone, while the other three were treated with 500 μM edaravone 2 h, 6 h, or 12 h after glutamate treatment, respectively. The cell viabilities of MTT test were 25%, 49%, 35%, and 33%, respectively (Figure 5(a)), and those of trypan blue staining were 22%, 40%, 32%, and 30% (Figure 5(b)). Treatment of edaravone at the time point of 2 h after glutamate achieved satisfying protection for SGNs against glutamate-induced cytotoxicity. But there was no significant improvement in cell viability when treated at later time points.

View Article: PubMed Central - PubMed

ABSTRACT

Glutamate is an important excitatory neurotransmitter in mammalian brains, but excessive amount of glutamate can cause &ldquo;excitotoxicity&rdquo; and lead to neuronal death. As bipolar neurons, spiral ganglion neurons (SGNs) function as a &ldquo;bridge&rdquo; in transmitting auditory information from the ear to the brain and can be damaged by excessive glutamate which results in sensorineural hearing loss. In this study, edaravone, a free radical scavenger, elicited both preventative and therapeutic effects on SGNs against glutamate-induced cell damage that was tested by MTT assay and trypan blue staining. Ho.33342 and PI double staining revealed that apoptosis as well as necrosis took place during glutamate treatment, and apoptosis was the main type of cell death. Oxidative stress played an important role in glutamate-induced cell damage but pretreatment with edaravone alleviated cell death. Results of western blot demonstrated that mechanisms underlying the toxicity of glutamate and the protection of edaravone were related to the PI3K pathway and Bcl-2 protein family.

No MeSH data available.


Related in: MedlinePlus