• experimental
  
• epidemiological
  

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Medical/biological Study (experimental study)

Green tea catechins protect rats from microwave-induced oxidative damage to heart tissue. med./biol.

PubMed Entry

Journal web site

Aim of study (according to author)
To study the effects of green tea catechins (antioxidants) on oxidative damage in the heart tissue of microwave exposed rats.
Background/further details:
The exposed rats received one of three diets: 1) catechin-free, 2) 0.25% catechin, or 3) 0.5% catechin. Each group consisted of ten rats. Rats were sacrificed 6 days after microwave irradiation

Endpoint

• effects on cardiovascular system: oxidative damage and antioxidative defense system in the heart

Exposure
General category: microwaves, CW (continuous wave), 2.45 GHz

Field characteristics	Parameters
2.45 GHz continuous wave (CW) exposure duration: continuous for 15 min.	power flux density: 40 mW/cm² (at a distance of 35 cm) SAR: 9.2 W/kg average over mass (whole body)

Exposed system:
animal (species/strain): rat/Sprague-Dawley
whole body exposure

Methods
Endpoint/Measurement parameters/Methodology

• effects on cardiovascular system: oxidative damage and antioxidative defense system (cytochrome P450 level; enzyme activities of NADPH-cytochrome P450 reductase, of superoxide dismutase and glutathione peroxidase; content of superoxide radical, lipofuscin and carbonyl groups (as index for oxidized proteins); lipid peroxidation (malondialdehyde content; thiobarbituric acid method))

Main outcome of study (according to author)
Cytochrome P450 levels in the catechin-free microwave exposed group were increased by 85% compared with the control group. However, they were 11% and 14% lower in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups than in the catechin-free group.
NADPH-cytochrome P450 reductase enzyme activity in the catechin free group was increased by 29%, compared to the control group, but it was significantly less in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups.
Superoxide dismutase activity in the catechin-free group was decreased by 34%, compared with the normal group, but in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups it was 19% and 25% higher compared to the catechin-free group. The enzyme activity of glutathione peroxidase in the catechin-free microwave exposed group was decreased by 28% but remained near normal value with catechin supplements.
Superoxide radical concentration in the catechin-free microwave exposed group was increased by 35% compared with the control group. However, superoxide radicals in the "microwave + 0.25 % catechin" and "microwave + 0.5 % catechin" groups were 11% and 12% lower, respectively, compared with the catechin-free group.
Microwave exposure significantly increased levels of thiobarbituric acid-reactive substances, carbonyl group values, and lipofuscin contents, but catechins partially overcame the effects of the microwave irradiation.
In conclusion, oxidative damage was induced by microwave exposure. However, green tea catechin supplementation significantly reduced oxidative damage by weakening the free radical generating system, and strengthening of the antioxidative system.

(Study character: medical/biological study, experimental study, full/main study)

Study funded by

• not stated

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