Increased serum enzyme activity in microwave-exposed rats

Area of Science:

• Biophysics
• Environmental Health
• Toxicology

Background:

• Microwave exposure effects on biological systems are a growing concern.
• Understanding thermal and non-thermal effects is crucial for safety assessments.
• Heat-stable serum enzymes can serve as biomarkers for cellular stress and injury.

Purpose of the Study:

• To investigate the effects of microwave exposure on heat-stable serum enzymes in rats.
• To determine a threshold body temperature for acute cellular injury induced by microwaves.
• To establish a tentative threshold for whole-body average absorption rate in adult rats.

Main Methods:

• Rats were exposed to microwaves (2.45 GHz) at varying intensities and durations.
• Colonic temperature was maintained at 41.5°C for 30 minutes in anesthetized rats.
• Serum enzyme levels (alkaline phosphatase, lactic dehydrogenase, GPT, GOT) were analyzed 24 hours post-exposure.

Main Results:

• Alkaline phosphatase and lactic dehydrogenase levels did not significantly change.
• Elevated serum glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) were observed in rats with elevated colonic temperatures.
• A threshold body temperature for acute cellular injury was identified, potentially in the liver, with mild enzyme elevations.

Conclusions:

• Microwave exposure can induce acute cellular injury, particularly at elevated body temperatures.
• A tentative threshold absorption rate of 14 W/kg for 4-hour exposure was derived for adult rats.
• Factors like exposure duration and body temperature regulation can influence injury thresholds.