Fig 1.
The average escape latency (AEL) of 80 male Wistar rats were detected by Morris water maze (WMW) training session, then 16 outliers were eliminated. The remaining 64 rats were randomly divided into 4 group. 16 rats of each group were divided and 8 rats were kept in each box. ELF-EMF exposure system was installed in room2. When the exposure started, rats of AD and AD+MF groups received D-galactose intraperitoneal and hippocampal injection. Con and MF groups were injected with same volume of normal saline(NS). 15min and 5d after terminateion of 60d ELF-EMF exposure, 5 rats from each group were decapitated after becoming deeply anesthetized, and the hippocampus were collected. Then pathological analysis and proteomics study were performed. The learning and memory of 11 rasts from each group were detected by MWM test session.
Fig 2.
The hippocampal injection site and pathologic change in the CA3 region after exposure to 50 Hz and 400 μT of ELF-EMF for 60 days.
(A-a): Hippocampal formation. (A-b, c): 1d and 7d after hippocampal injection, HE staining, →: injection site. (B) HE staining. CA3 region was enlarge in the right bottom box. →: nuclear contraction. (C) Electron microscope observation. →: neurofibrillary tangle; ▲:lipofuscin deposition; ∆: well and focal cavitations of mitochondria.
Fig 3.
Weight and average escape latency (AEL) changes of rats during and after exposed to 50 Hz and 400 μT ELF-EMF for 60 days.
(A) Weight changes of rats during exposure. Three weeks after ELF-EMF exposure started, compared with AD group the weight gain of AD+MF group significantly decreased (P = 0.007). This change can be seen at four week between group MF and Con (P = 0.017). (B) Swimming trajectory of rats 3 days after termination of exposure. The water surface was divided into I-IV quadrants, and the platform was positioned at the center of quadrant I. (C) Swimming speed changes of rats 0–3days after termination of exposure. (D) AEL changes of rats 0–3days after termination of exposure. (E) Percent of time spent in quadrant at 4day after termination of exposure. vs Con ** P < 0.01 * P < 0.05, vs MF ▲▲P < 0.01 ▲P < 0.05, vs AD P < 0.01 P < 0.05.
Fig 4.
Nissl bodies changes in the CA3 region of rat hippocampus after exposure to 50 Hz and 400 μT of ELF-EMF for 60 days.
(A) Toluidine blue staining. (B)Image analysis results of Nissl bodies. The mean optical density (MOD) was calculated and used to judge the content change of Nissl bodies. vs Con ** P < 0.01 * P < 0.05, vs MF ▲▲P < 0.01 ▲P < 0.05, vs AD P < 0.01 P < 0.05.
Table 1.
The amount of differential proteins expressed in the rat hippocampus after exposure to 50 Hz and 400 μT ELF-EMF for 60 days.
Table 2.
NCBI database results from 15 differential proteins identified by mass spectrometry.