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Updated: Mar 18, 2026
Determination of Mitochondrial Membrane Potential and Reactive Oxygen Species in Live Rat Cortical Neurons
Published on: May 23, 2011
Oxidative damage induced by a novel porphyrin on rat brain mitochondria and its possible implications in therapy
S R Chatterjee1, J P Kamat2, S J Shetty1
1a Department of Chemistry , Indian Institute of Technology , Bombay , India.
Abstract:
Free radical-induced oxidative damage is involved in several pathological disorders. On the other hand, selective induction of peroxidation in diseased tissue is a promising approach to the treatment of cancer by photodynamic therapy. In this study we have used rat brain mitochondria as a model to evaluate the ability of a new water soluble porphyrin, 5,10,15,20-tetrakis[4-(carboxymethyleneoxy)phenyl]porphyrin (T4CPP), to induce peroxidative damage during photosensitization. Peroxidation in mitochondria, one of the crucial targets of the photodynamic effect, was assessed from the formation of thiobarbituric acid reactive substances and lipid hydroperoxides. The effect on mitochondrial function was estimated from the loss of a mitochondrial marker enzyme, succinate dehydrogenase (SDH). The photodamage was observed to be time- and concentration-dependent of T4CPP. Inhibition studies suggested involvement of singlet oxygen ((1)O2) and, to a lesser extent, of hydroxyl (OH), peroxyl (ROO(-)) and superoxide radicals (O2(-)) in the photodamage. The addition of γ-linolenic acid (a promoter of lipid peroxidation) to the system led to an enhancement of the T4CPP-induced peroxidative damage. Thus, our study indicated that the combination of γ-linolenic acid and T4CPP could enhance the photodynamic effect and has potential applications in photodynamic therapy.
Insights
This study shows that a new photosensitizer, T4CPP, combined with γ-linolenic acid, effectively damages mitochondria. This combination enhances photodynamic therapy for cancer treatment by increasing oxidative damage.
Area of Science:
- Biochemistry
- Cell Biology
- Photochemistry
Background:
- Oxidative damage from free radicals contributes to various diseases.
- Photodynamic therapy (PDT) offers a promising cancer treatment by selectively inducing peroxidation in diseased tissues.
Purpose of the Study:
- To evaluate the potential of a novel water-soluble porphyrin, T4CPP, in inducing oxidative damage in rat brain mitochondria during photosensitization.
- To assess the role of reactive oxygen species and lipid peroxidation in T4CPP-mediated photodamage.
Main Methods:
- Mitochondria were used as a model system to study T4CPP-induced photodamage.
- Lipid peroxidation was measured via thiobarbituric acid reactive substances and lipid hydroperoxides.
- Mitochondrial function was assessed by monitoring succinate dehydrogenase (SDH) activity.
Main Results:
- T4CPP-induced photodamage was dependent on both time and concentration.
- Inhibition studies indicated the involvement of singlet oxygen, hydroxyl radicals, peroxyl radicals, and superoxide radicals.
- The addition of γ-linolenic acid significantly enhanced T4CPP-induced peroxidative damage.
Conclusions:
- T4CPP effectively induces mitochondrial peroxidative damage upon photosensitization.
- The combination of γ-linolenic acid and T4CPP amplifies the photodynamic effect.
- This synergistic approach holds potential for enhancing photodynamic therapy in cancer treatment.
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