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Effect of methyl methacrylate on mitochondrial function and structure
1Department of Prosthetic Dentistry, Academic Medical School in Gdański, Poland.
Abstract:
1. Treatment of isolated rat liver mitochondria with methyl methacrylate (MM) produced membrane disruption as evidenced by the release of citrate synthase, and changes in the ultrastructure of mitochondria. 2. At concentration 0.1%, MM uncoupled oxidative phosphorylation as evidenced by stimulation of state 4 respiration supported either by pyruvate plus malate or succinate (+rotenone) and ATP-ase activity in intact mitochondria. 3. At concentration 1% MM stimulated ATP-ase activity in intact mitochondria and succinate (+ rotenone) oxidation at state 4 and was without effect on this substrate oxidation at state 3. 4. MM inhibited pyruvate plus malate oxidation either at state 3 or in the presence of uncoupling agents. 5. MM inhibited the NADH oxidase of electron transport particles at a concentration which failed to inhibit either succinic oxidase or the NADH-ferricyanide reductase activity. 6. The data presented suggest that in the isolated mitochondria MM inhibits NADH oxidation in the vicinity of the rotenone sensitive site of complex I. 7. The general conclusion is that MM may block an electron transport and to uncouple oxidative phosphorylation in rat liver mitochondria. The overall in vitro effect would be to prevent ATP synthesis which could result in cell death under in vivo conditions.
Insights
Methyl methacrylate (MM) disrupts rat liver mitochondria, uncoupling oxidative phosphorylation and inhibiting electron transport. This prevents ATP synthesis, potentially leading to cell death.
Area of Science:
- Biochemistry
- Toxicology
- Mitochondrial Biology
Background:
- Mitochondria are crucial for cellular energy production.
- Understanding the effects of chemical compounds on mitochondrial function is vital for toxicology.
Purpose of the Study:
- To investigate the effects of methyl methacrylate (MM) on isolated rat liver mitochondria.
- To determine the impact of MM on oxidative phosphorylation and electron transport.
Main Methods:
- Treatment of isolated rat liver mitochondria with varying concentrations of MM.
- Assessing mitochondrial membrane integrity via citrate synthase release.
- Measuring oxidative phosphorylation (respiration states 3 and 4) and ATP-ase activity.
- Evaluating electron transport chain complex activity (NADH oxidase, succinic oxidase).
Main Results:
- MM caused mitochondrial membrane disruption and ultrastructural changes.
- At 0.1%, MM uncoupled oxidative phosphorylation and stimulated ATP-ase activity.
- At 1%, MM further stimulated ATP-ase activity and state 4 respiration.
- MM inhibited pyruvate plus malate oxidation and NADH oxidase activity, suggesting inhibition near Complex I.
- MM blocked electron transport and uncoupled oxidative phosphorylation.
Conclusions:
- Methyl methacrylate disrupts mitochondrial function by inhibiting electron transport and uncoupling oxidative phosphorylation.
- MM's in vitro effects prevent ATP synthesis, suggesting potential in vivo toxicity and cell death.