The increase in viscosity and peroxidation of sarcoplasmic reticulum membrane lipids in isadrine myocarditis
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L V Lyzlova1, V R Persianova, A E Antipenko
1Department of Biochemistry, Leningrad State University, USSR.
Abstract:
The viscosity of membranes isolated from sarcoplasmic reticulum of rabbits with isadrine myocarditis was studied, using pyrene as a hydrophobic fluorescent probe. The increase in the viscosity of membranes from injured heart occurred at lower temperatures and was sharper than in the case of intact heart in both "free" and "bound" lipid domains. The increase in the lipid viscosity under myocarditis was associated with decreased Ca++, Mg++ -ATPase and cAMP-dependent protein kinase activities and with an elevated content of lipid peroxidation products.
Insights
Myocarditis increases heart membrane viscosity, affecting lipid domains even at lower temperatures. This change correlates with reduced enzyme activity and increased lipid peroxidation in injured heart tissue.
Area of Science:
- Biochemistry
- Cardiovascular Physiology
- Membrane Biophysics
Background:
- Sarcoplasmic reticulum membranes are crucial for cardiac muscle function.
- Myocarditis, or heart inflammation, can significantly alter cardiac tissue properties.
- Understanding changes in membrane biophysical properties is key to understanding cardiac dysfunction.
Purpose of the Study:
- To investigate the effect of isadrine-induced myocarditis on the viscosity of sarcoplasmic reticulum membranes.
- To explore the relationship between altered membrane viscosity and biochemical changes in the injured heart.
Main Methods:
- Isolation of sarcoplasmic reticulum membranes from rabbit hearts.
- Utilizing pyrene as a hydrophobic fluorescent probe to measure membrane viscosity.
- Assessing Ca++, Mg++-ATPase and cAMP-dependent protein kinase activities.
- Quantifying lipid peroxidation products.
Main Results:
- A significant increase in membrane viscosity was observed in myocarditis-affected hearts compared to controls.
- The viscosity increase occurred at lower temperatures and was more pronounced in both "free" and "bound" lipid domains.
- Decreased activities of Ca++, Mg++-ATPase and cAMP-dependent protein kinase were noted.
- Elevated levels of lipid peroxidation products were found in the injured heart membranes.
Conclusions:
- Isadrine-induced myocarditis alters the biophysical properties of sarcoplasmic reticulum membranes, increasing lipid viscosity.
- The observed increase in viscosity is linked to impaired enzymatic functions and oxidative stress, indicated by lipid peroxidation.
- These findings highlight the impact of myocarditis on cardiac membrane integrity and function.