Medical/biological study (experimental study)

The effects of terahertz radiation on human keratinocyte primary cultures and neural cell cultures med./bio.

By: Bourne N, Clothier RH, D'Arienzo M, Harrison P

Published in: Altern Lab Anim 2008; 36 (6): 667-684

Aim of study (acc. to author)

To investigate the effects of long-term and/or repeated exposure to terahertz waves on human keratinocyte primary cultures and neural cell cultures.

Background/further details

Two different cell types were used to investigate the effects of terahertz waves on the barrier function of the skin (primary cultures of human keratinocytes) and the eye (human corneal epithelium cells). Human corneal epithelium cells are only protected by a tear film, thus the eye is less protected than the skin. The cell line ND7/23 displays the characteristics of sensory neurones.
Following control groups were used: 1) sham exposed cells, 2) negative controls (UVA exposure) and 3) positive controls (UVB exposure and heat shock treatment (43°C, 60 min)).

Endpoint

cell viability/cell division/proliferation: cell proliferation
stress response (heat-shock protein HSP70, glutathione), cell differentiation

Exposure

Exposure	Parameters
Exposure 1: 14 THz Modulation type: pulsed Exposure duration: continuous for 10 min to 24 hr single exposure	power: 250 mW minimum (peak value) power: 1,000 mW maximum (peak value) power density: 24 mW/cm² minimum (peak value) power density: 62 mW/cm² maximum (peak value)
Exposure 2: 14 THz Modulation type: pulsed Exposure duration: 2 times 24 hr with a 48 hr interval between them repeated exposure	power: 250 mW minimum (peak value) power: 1,000 mW maximum (peak value) power density: 24 mW/cm² minimum (peak value) power density: 62 mW/cm² maximum (peak value)
Exposure 3: 14 THz Modulation type: pulsed Exposure duration: continuous for 24 hr single exposure with UVB co-exposure	power: 250 mW minimum (peak value) power: 1,000 mW maximum (peak value) power density: 24 mW/cm² minimum (peak value) power density: 62 mW/cm² maximum (peak value)

Exposure 1

Main characteristics

Frequency	14 THz
Type	electromagnetic field
Exposure duration	continuous for 10 min to 24 hr
Additional info	single exposure

Modulation

Modulation type	pulsed
Pulse width	80 ns
Repetition frequency	50 kHz

Exposure setup

Exposure source	millimeter wave generator
Distance between exposed object and exposure source	6.7 cm
Setup	culture plates placed inside a CO₂ incubator; exposure directed on the base of the culture plates

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	250 mW	minimum	measured	-	peak value
power	1,000 mW	maximum	measured	-	peak value
power density	24 mW/cm²	minimum	measured	-	peak value
power density	62 mW/cm²	maximum	measured	-	peak value

Exposure 2

Main characteristics

Frequency	14 THz
Type	electromagnetic field
Exposure duration	2 times 24 hr with a 48 hr interval between them
Additional info	repeated exposure

Modulation

Modulation type	pulsed
Pulse width	80 ns
Repetition frequency	50 kHz

Exposure setup

Exposure source	same setup as exposure 1
Distance between exposed object and exposure source	6.7 cm

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	250 mW	minimum	measured	-	peak value
power	1,000 mW	maximum	measured	-	peak value
power density	24 mW/cm²	minimum	measured	-	peak value
power density	62 mW/cm²	maximum	measured	-	peak value

Exposure 3

Main characteristics

Frequency	14 THz
Type	electromagnetic field
Exposure duration	continuous for 24 hr
Additional info	single exposure with UVB co-exposure

Modulation

Modulation type	pulsed
Pulse width	80 ns
Repetition frequency	50 kHz

Exposure setup

Exposure source	same setup as exposure 1
Distance between exposed object and exposure source	6.7 cm
Setup	with or without prior exposure to 30 mJ/cm² UVB

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power	250 mW	minimum	measured	-	peak value
power	1,000 mW	maximum	measured	-	peak value
power density	24 mW/cm²	minimum	measured	-	peak value
power density	62 mW/cm²	maximum	measured	-	peak value

Exposed system:

intact cell/cell culture
ND7/23 cells (neuronal cell line); human primary keratinocytes and human corneal epithelial cells

Methods Endpoint/measurement parameters/methodology

cell function: barrier function (corneal epithelial cells; fluorescein leakage assay)
cell viability/cell division/proliferation: cell proliferation (resazurin reduction assay)
morphol./histopathol. changes: cell morphology (ceratinocytes; phase-contrast microscopy), cell differentiation (ceratinocytes; fluorescein cadaverine uptake assay)
stress response (level of heat-shock protein HSP70 (ceratinocytes, corneal epithelial cells; Western blot, ELISA), oxidative stress (ND7/23; glutathione assay)

Investigated system:

intact cell/cell culture
cell lysate, proteines

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

No effects of long-term and/or repeated exposure to terahertz waves were found on the investigated parameters of the three studied cell lines.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Northwest Science Fund (NWSF), UK

Hintzsche H et al. (2011): Terahertz radiation induces spindle disturbances in human-hamster hybrid cells
Wilmink GJ et al. (2011): In vitro investigation of the biological effects associated with human dermal fibroblasts exposed to 2.52 THz radiation
Wilmink GJ et al. (2010): Determination of death thresholds and identification of Terahertz (THz)-specific gene expression signatures
Tong Y et al. (2009): Millimeter-wave exposure promotes the differentiation of bone marrow stromal cells into cells with a neural phenotype
Korenstein-Ilan A et al. (2008): Terahertz radiation increases genomic instability in human lymphocytes
Clothier RH et al. (2003): Effects of THz exposure on human primary keratinocyte differentiation and viability
Woodward RM et al. (2002): Terahertz pulse imaging in reflection geometry of human skin cancer and skin tissue
Markelz AG et al. (2000): Pulsed Terahertz Spectroscopy of DNA, Bovine Serum Albumin and Collagen between 0.1 and 2.0 THz

The effects of terahertz radiation on human keratinocyte primary cultures and neural cell cultures med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 3

Main characteristics

Modulation

Exposure setup

Parameters

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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