# RF-020 — Blinded rat histology with significant findings at two of three exposure levels

Why this matters
When brain tissue was examined weeks after a two-hour RF exposure, a blinded examiner found higher scores for dark-staining nerve cells in some rat groups. This makes delayed tissue changes worth examining. The lowest dose was nonsignificant and independent replication did not confirm the result; permanent human injury was not established.

Id: RF-020

Author: Salford et al.

Full Authors: Leif G. Salford; Arne E. Brun; Jacob L. Eberhardt; Lars Malmgren; Bertil R. R. Persson

Year: 2003

Title: Nerve cell damage in mammalian brain after exposure to microwaves from GSM mobile phones

Journal: Environmental Health Perspectives

Citation: Salford LG, Brun AE, Eberhardt JL, Malmgren L, Persson BRR. Nerve cell damage in mammalian brain after exposure to microwaves from GSM mobile phones. Environ Health Perspect. 2003;111(7):881-883. doi:10.1289/ehp.6039.

Doi: 10.1289/ehp.6039

Pmid: 12782486

Topic: Neuropathology and blood-brain barrier

Verification Group: Original text reviewed

Record Role: Original text reviewed

Featured: True

Exposure: GSM telephone fed into TEM cells, no voice modulation; nominal 915-MHz programme. Average whole-body SAR 0.002, 0.02, or 0.2 W/kg for 2 h; corresponding peak power densities 0.24, 2.4, 24 W/m². Brain SAR distribution simulated by FDTD, varying <6 dB. Room/cell air temperature controlled.

Design: 32 male and female Fischer 344 rats aged 12-26 weeks, 8/group including sham; awake, movable within chamber. Perfusion fixation; cresyl-violet staining and albumin immunohistochemistry. Neuropathologist blinded; dark-neuron score 0/1/2 (none/occasional, moderate, abundant).

Finding: After one 2-h exposure and approximately 50 days' recovery, the blinded semiquantitative dark-neuron score differed across four groups (Kruskal-Wallis p<0.002). Individual comparisons with sham: 0.002 W/kg p<0.2; 0.02 W/kg p=0.01; 0.2 W/kg p=0.03. The lowest group was not significant. Changes occurred particularly in cortex, hippocampus and basal ganglia.

Boundary: Small mixed-sex, broad-age sample and subjective ordinal endpoint. Histology is a reported pathological endpoint, but permanent functional injury, apoptosis and human disease were not established. Direct replication did not confirm the outcome (Masuda 2009). Rat whole-body SAR cannot certify human local-SAR compliance.

Related: Same Lund programme as RF-027, RF-028, RF-029 and CTX-005. CTX-006 is a specific independent replication attempt, not a general safety review.

Protection Question: Is the delayed dark-neuron signal reproducible and specific to injury rather than tissue handling or scoring? Its small sample, nonsignificant lowest dose and nonconfirming replication prevent a harmful human exposure threshold.

Access: Original three-page journal PDF read, including embedded correction; Scite supplied abstract only

Locator: pp. 881-882 Materials and Methods; p.882 Results, Figure 3 and caption; p.883 Correction

Notice: Embedded Correction on p.883 replaces Figure 1 from earlier immediately-sacrificed animals with present-study specimens (sham and 2 mW/kg). No separate notice DOI identified. Scite metadata did not surface this correction. No retraction/concern found in targeted search.

Funding: Swedish Council for Work Life Research grant (p.881).

Conflicts: Authors declare no conflict of interest (p.881).

Source Url: https://doi.org/10.1289/ehp.6039

Retrieval Links: https://doi.org/10.1289/ehp.6039 | https://pmc.ncbi.nlm.nih.gov/articles/PMC1241519/ | https://www.electrosmog.be/doc/sc/cerveau/Salford-Leif_Nerve-cell-damage-in-mammalian-brain-after-exposure-to-microwaves-from-GSM-mobile-phones_2003.pdf | https://pubmed.ncbi.nlm.nih.gov/12782486/

Verification Date: 2026-10-20