Medical/biological study (experimental study)

Comparative analysis of the protective effects of melatonin and caffeic acid phenethyl ester (CAPE) on mobile phone-induced renal impairment in rat med./bio.

By: Özgüner F, Oktem F, Armagan A, Yilmaz R, Koyu A, Demirel R, Vural H, Uz E

Published in: Mol Cell Biochem 2005; 276 (1-2): 31-37

Aim of study (acc. to author)

To compare the protective effects of melatonin and CAPE against 900 MHz electromagnetic field-induced renal tubular injury.

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.
ROS such as superoxide and nitric oxide may contribute to the pathophysiology of electromagnetic irradiation-induced renal impairment.

Endpoint

oxidative stress-induced renal impairment

Exposure

- mobile communications
- mobile phone

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: CW Exposure duration: repeated daily exposure, 30 min/day for 10 days	power: 2 W peak value power density: 1.04 mW/cm² mean SAR: 1.04 W/kg mean

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	repeated daily exposure, 30 min/day for 10 days

Modulation

Modulation type	CW

Exposure setup

Exposure source	dipole antenna RF generator
Chamber	The exposure system consisted of a ventilated plastic tube cage (12 cm long x 5.5 cm in diameter) and a dipole antenna.
Setup	The whole body of the rat was positioned in close contact above the antenna.
Additional info	Rats were allocated to four groups: sham exposed, EMR exposed, EMR exposed + melatonin treated, and EMR exposed + CAPE treated. Melatonin dissolved in ethanol/saline was injected s.c., and CAPE was injected i.p. daily immediately before exposure. Sham exposed rats were injected with isotonic saline solution instead.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	2 W	peak value	-	-	-
power density	1.04 mW/cm²	mean	measured	-	-
SAR	1.04 W/kg	mean	measured	-	-

Measurement and calculation details

Power density measurements were made using an EMF meter.

Exposed system:

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: content of malondialdehyde (index of lipid peroxidation), urinary N-acetyl-beta-D-glucosaminidase (NAG, a marker of renal tubular injury) (spectrophotometry)
oxidative stress-induced renal impairment (content of different markers, see "molecular biosynthesis"); antioxidant status (activities of superoxide dismutase, catalase, glutathione peroxidase)

Investigated system:

kidney tissue homogenates; urine samples

Investigated organ system:

kidney

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Urinary NAG and renal malondialdehyde were increased in electromagnetic field exposed animals while both melatonin and CAPE caused a significant reduction in the levels of these parameters but the effect of melatonin was more potent than that of CAPE. Likewise, renal superoxide dismutase and glutathione peroxidase activities were decreased in exposed rats while melatonin caused a significant increase in the activities of these antioxidant enzymes but CAPE did not.
In conclusion, melatonin and CAPE prevent renal tubular injury by reducing oxidative stress and protect the kidney from oxidative damage induced by mobile phone (900 MHz). Nevertheless, melatonin seems to be a more potent antioxidant in comparison to CAPE in kidney.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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