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Updated: Jul 7, 2026
Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons
Published on: May 23, 2011
Mitochondrial-dependent manganese neurotoxicity in rat primary astrocyte cultures
Zhaoobao Yin1, Judy L Aschner, Ana Paula dos Santos
1Department of Pediatrics, Vanderbilt University Medical Center, TN, USA.
Abstract:
Chronic exposure to excessive levels of Mn results in a movement disorder termed manganism, which resembles Parkinson's disease (PD). The pathogenic mechanisms underlying this disorder are not fully understood. Several lines of evidence implicate astrocytes as an early target of Mn neurotoxicity. In the present study, we investigated the effects of Mn on mitochondrial function. Primary astrocyte cultures were prepared from cerebral cortices of one-day-old Sprague-Dawley rats. We have examined the cellular toxicity of Mn and its effects on the phosphorylation of extracellular signal-regulated kinase (ERK) and activation of the precursor protein of caspase-3. The potentiometric dye, tetramethyl rhodamine ethyl ester (TMRE), was used to assess the effect of Mn on astrocytic mitochondrial inner membrane potential (DeltaPsi(m)). Our studies show that, in a concentration-dependent manner, Mn induces significant (p<0.05) activation of astrocyte caspase-3 and phosphorylated extracellular signal-regulated kinase (p-ERK). Mn treatment (1 and 6 h) also significantly (p<0.01) dissipates the DeltaPsi(m) in astrocytes as evidenced by a decrease in mitochondrial TMRE fluorescence. These results suggest that activations of astrocytic caspase-3 and ERK are involved in Mn-induced neurotoxicity via mitochondrial-dependent pathways.
Insights
Manganese (Mn) exposure causes manganism, a Parkinson's-like disorder. This study reveals Mn damages astrocyte mitochondria, activating cell death pathways and contributing to neurotoxicity.
Area of Science:
- Neuroscience
- Toxicology
- Cell Biology
Background:
- Chronic manganese (Mn) exposure leads to manganism, a movement disorder resembling Parkinson's disease (PD).
- Astrocytes are implicated as early targets in Mn neurotoxicity.
- The precise mechanisms of Mn-induced neurotoxicity, particularly concerning mitochondrial function, remain unclear.
Purpose of the Study:
- To investigate the effects of Mn on astrocyte mitochondrial function.
- To examine Mn-induced cellular toxicity, including caspase-3 activation and extracellular signal-regulated kinase (ERK) phosphorylation.
- To assess the impact of Mn on mitochondrial inner membrane potential (DeltaPsi(m)) in astrocytes.
Main Methods:
- Primary astrocyte cultures were established from rat cerebral cortices.
- Cellular toxicity was evaluated by measuring caspase-3 activation and ERK phosphorylation.
- Mitochondrial membrane potential was assessed using the potentiometric dye tetramethyl rhodamine ethyl ester (TMRE).
Main Results:
- Mn exposure significantly activated astrocyte caspase-3 and phosphorylated ERK in a concentration-dependent manner.
- Mn treatment led to a significant dissipation of astrocytic mitochondrial inner membrane potential (DeltaPsi(m)).
- Decreased TMRE fluorescence indicated Mn-induced mitochondrial dysfunction.
Conclusions:
- Astrocyte caspase-3 and ERK activation are involved in Mn-induced neurotoxicity.
- Manganese neurotoxicity appears to operate through mitochondrial-dependent pathways in astrocytes.
- These findings highlight the critical role of astrocytes and mitochondrial dysfunction in the pathogenesis of manganism.
