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Updated: Jun 5, 2026

Caspase-3 Activity in the Rat Amygdala Measured by Spectrofluorometry After Myocardial Infarction
Published on: January 12, 2016
[Relationship between hypoxia-induced apoptosis and caspases-3 activation, intracellular calcium overload in
Zhou Zhou1, Xiao-hua Wang, Guang-xu Zhu
1Department of Occupational Health, Third Military Medical University, Chongqing 400038, China.
Insights
Hypoxia triggers cardiomyocyte apoptosis via Caspase-3 activation. Intracellular calcium overload plays a key role in this process, highlighting potential therapeutic targets.
Area of Science:
- Cardiology
- Cell Biology
- Biochemistry
Context:
- Hypoxia, a condition of oxygen deprivation, is a critical factor in cardiovascular diseases.
- Understanding cellular mechanisms of injury during hypoxia is vital for developing treatments.
- Cardiomyocytes are particularly vulnerable to hypoxic damage.
Purpose:
- To investigate the impact of hypoxia on Caspase activation in cardiomyocytes.
- To elucidate the role of intracellular calcium in hypoxia-induced Caspase activation and apoptosis.
Summary:
- Hypoxia induces mitochondrion-dependent Caspase-3 activation, leading to cardiomyocyte apoptosis.
- Mitochondrial cytochrome c release and Caspase-3 mRNA expression increase post-hypoxia.
- Intracellular calcium overload precedes cytochrome c release and Caspase-3 activation.
Impact:
- Findings reveal a critical pathway linking hypoxia, calcium signaling, and cardiomyocyte death.
- Inhibiting Caspase-3 or chelating intracellular calcium demonstrates a protective effect against hypoxic injury.
- This research provides insights into potential therapeutic strategies for hypoxic heart conditions.
Aim:
To explore the effects of hypoxia on Caspases activation in cardiomyocyte and role of intracellular calcium in this event in cardiomyocytes.
Methods:
After hypoxia 0 min, 30 min, 1 h, 3 h, 6 h, 12 h, 24 h, apoptotic cell percentage was determined with Hoechst 33342 straining. Expressions of Caspases-3 mRNA and release of mitochondrial cytochrome c in primary culture of cardiomyocytes were determined by using RT-PCR and Western blotting respectively.
Results:
Elevation of Cyt c in cytosol was in accordance with the decline in mitochondrial Cyt c content. Significant increase in Cyt c in cytosol appeared at 12 h post hypoxia and peaked at 24 h while Cyt c in mitochondria could not be detected at 24 h post hypoxia. Hypoxia up-regulated Caspases-3 mRNA expressions beginning at 3 h post hypoxia. Intracellular calcium overload occurred earlier than release of mitochondrial Cyt c and the activation of Caspase-3 during the hypoxic insult. Inhibition of Caspase-3 activation and pretreatment with calcium chelator BAPTA/AM offered a marked protective effect on hypoxia induced cardiomyocyte apoptosis.
Conclusion:
Hypoxia can induce mitochondrion-dependent Caspase-3 activation in cardiomyocytes and therefore leads to cell apoptosis. Increase of intracellular Ca2+ plays an important role in the activation of Caspase-3 and the induction of apoptosis in cardiomyocytes.
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