Medical/biological study (experimental study)

Protective effects of melatonin and caffeic acid phenethyl ester against retinal oxidative stress in long-term use of mobile phone: a comparative study med./bio.

By: Özgüner F, Bardak Y, Comlekci S

Published in: Mol Cell Biochem 2006; 282 (1-2): 83-88

Aim of study (acc. to author)

To compare the protective effects of melatonin and CAPE against 900 MHz electromagnetic field-induced retinal oxidative stress.

Background/further details

Caffeic acid phenethyl ester (CAPE) is one of the major components of honeybee propolis. It has been used in folk medicine for many years in Middle East countries. Melatonin and CAPE were found to be potent free radical scavengers and antioxidants.
Melatonin (100 µg/kg) or CAPE (10 µM/ml per kg per day) were administered daily for 60 days to the animals prior to their electromagnetic field exposure.

Endpoint

oxidative stress-induced retinal impairment

Exposure

- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: repeated daily exposure for 30 min/day for 60 days	power: 2 W peak value power density: 1.04 mW/cm² SAR: 0.016 W/kg average over mass (whole body) SAR: 4 W/kg average over mass (brain)

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	repeated daily exposure for 30 min/day for 60 days

Modulation

Modulation type	pulsed
Repetition frequency	217 Hz

Exposure setup

Exposure source	dipole antenna
Setup	A special exposure device with six-exposure antennas for insulated exposure was used. The exposure system for an animal consisted of a plastic tube cage (length 12 cm, diameter 5 cm) and a half wave dipole antenna. The head of the rat was positioned in close contact above the dipole antenna. The tube was ventilated from head to tail.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	2 W	peak value	-	-	-
power density	1.04 mW/cm²	-	measured	-	-
SAR	0.016 W/kg	average over mass	measured	whole body	-
SAR	4 W/kg	average over mass	measured	brain	-

Exposed system:

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: content of malondialdehyde (index of lipid peroxidation) and nitric oxide (an oxidant product) (spectrophotometry)
oxidative stress-induced retinal impairment (content of different markers, see "molecular biosynthesis"); antioxidant status (activities of superoxide dismutase, catalase, glutathione peroxidase)

Investigated system:

retina homogenates; cell supernatants

Investigated organ system:

sense organs
eye (retina)

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Retinal levels of nitric oxide and malondialdehyde increased in the electromagnetic field exposed rats while both melatonin and CAPE caused a significant reduction in the levels of nitric oxide and malondialdehyde.
Likewise, retinal superoxide dismutase, glutathione peroxidase and catalase activities decreased in electromagnetic field exposed animals while melatonin and CAPE caused a significant increase in the activities of these antioxidant enzymes in the exposed animals to higher levels than those of control rats.
In conclusion, melatonin and CAPE reduce retinal oxidative stress after long-term exposure to 900 MHz emitting mobile phone. Nevertheless, there was no statistically significant difference between the efficacies of these two antioxidants against to electromagnetic field induced oxidative stress. The difference was in only glutathione peroxidase activity. Melatonin stimulated the retinal glutathione peroxidase activity more efficiently than CAPE did.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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