Increased myocardial catalase in rats fed ethanol

Area of Science:

• Biochemistry
• Cardiovascular Physiology
• Toxicology

Background:

• Ethanol metabolism is primarily hepatic, but extrahepatic metabolism, particularly in the heart, is increasingly recognized.
• Catalase is an enzyme involved in peroxide metabolism and can also metabolize ethanol.

Purpose of the Study:

• To investigate the effects of chronic dietary ethanol consumption on myocardial catalase activity and cardiac function in rats.
• To examine the impact of ethanol on myocardial morphology at the cellular and ultrastructural levels.
• To explore the potential role of myocardial catalase in response to chronic ethanol exposure.

Main Methods:

• Rats were fed diets with 36% of calories from ethanol for 5 and 18 weeks.
• Myocardial and hepatic catalase activity were measured.
• Cytochemical and electron microscopy were used to assess myocardial peroxisomes and ultrastructure.
• Hemodynamic parameters, including left ventricle systolic pressure and mean arterial pressure, were recorded.

Main Results:

• Myocardial catalase activity increased by 45.9 IU/mg protein after 5 weeks of ethanol intake, remaining elevated at 18 weeks, while hepatic catalase showed no significant change.
• Increased myocardial catalase activity correlated with an increase in myocardial peroxisomes.
• No significant gross or light-microscopic abnormalities were found in the myocardium.
• Hemodynamic studies revealed decreased left ventricle systolic pressure and mean arterial pressure after 5 weeks of ethanol exposure.

Conclusions:

• Chronic dietary ethanol intake leads to a significant increase in myocardial catalase activity in rats.
• The increased myocardial catalase, associated with peroxisome proliferation, may play a metabolic and potentially protective role in the heart during prolonged ethanol exposure.
• Despite altered hemodynamics, significant cardiac structural damage was not evident at the studied time points.