Extremely low frequency magnetic field (50 Hz, 0.5 mT) reduces oxidative stress in the brain of gerbils submitted to global cerebral ischemia.

Magnetic field as ecological factor has influence on all living beings. The aim of this study was to determine if extremely low frequency magnetic field (ELF-MF, 50 Hz, 0.5 mT) affects oxidative stress in the brain of gerbils submitted to 10-min global cerebral ischemia. After occlusion of both carotid arteries, 3-month-old gerbils were continuously exposed to ELF-MF for 7 days. Nitric oxide and superoxide anion production, superoxide dismutase activity and index of lipid peroxidation were examined in the forebrain cortex, striatum and hippocampus on the 7(th) (immediate effect of ELF-MF) and 14(th) day after reperfusion (delayed effect of ELF-MF). Ischemia per se increased oxidative stress in the brain on the 7(th) and 14(th) day after reperfusion. ELF-MF also increased oxidative stress, but to a greater extent than ischemia, only immediately after cessation of exposure. Ischemic gerbils exposed to ELF-MF had increased oxidative stress parameters on the 7(th) day after reperfusion, but to a lesser extent than ischemic or ELF-MF-exposed animals. On the 14(th) day after reperfusion, oxidative stress parameters in the brain of these gerbils were mostly at the control levels. Applied ELF-MF decreases oxidative stress induced by global cerebral ischemia and thereby reduces possible negative consequences which free radical species could have in the brain. The results presented here indicate a beneficial effect of ELF-MF (50 Hz, 0.5 mT) in the model of global cerebral ischemia

One-way analysis of variance.

<p>df – degrees of freedom; η_p² – partial eta-squared.</p

ELF-MF effect on SOD activity in the brain of gerbils submitted to global cerebral ischemia.

<p>Each bar represents mean ± SEM (n = 6–8 animals per group). **p<0.01 and ***p<0.001 indicate significant differences compared to ELF-MF; ^♦♦♦p<0.001 indicates significant differences compared to Ischemia (one-way analysis of variance followed by LSD test).</p

ELF-MF effect on O₂⁻ content in the brain of gerbils submitted to global cerebral ischemia.

<p>Each bar represents mean ± SEM (n = 6–8 animals per group). **p<0.01 and ***p<0.001 indicate significant differences compared to ELF-MF; ^♦p<0.05, ^♦♦p<0.01 and ^♦♦♦p<0.001 indicate significant differences compared to Ischemia (one-way analysis of variance followed by LSD test).</p

An Extremely Low Frequency Magnetic Field and Global Cerebral Ischemia Affect Pituitary ACTH and TSH Cells in Gerbils.

The neuroendocrine system can be modulated by a magnetic field and cerebral ischemia as external and internal stressors, respectively. This study deals with the separate or combined effects of an extremely low frequency (ELF) magnetic field (50 Hz, average magnetic field of 0.5 mT) for 7 days and global cerebral ischemia for 10 min on the morpho-functional features of pituitary adrenocorticotrophic (ACTH) and thyrotrophic (TSH) cells in 3-month-old gerbils. To determine the immediate and delayed effects of the applied stressors, measurements were made on the 7th and 14th days after the onset of the experiment. The ELF magnetic field and 10-min global cerebral ischemia, separately and particularly in combination, decreased (P < 0.05) the volume density of ACTH cells, while only in combination were intracellular ACTH content and plasma ACTH concentration increased (P < 0.05) on day 7. The ELF magnetic field elevated serum TSH concentration on day 7 and intracellular TSHβ content on day 14 (P < 0.05). Also, 10-min global cerebral ischemia alone increased serum TSH concentration (P < 0.05), while in combination with the ELF magnetic field it elevated (P < 0.05) intracellular TSHβ content on day 14. In conclusion, an ELF magnetic field and/or 10-min global cerebral ischemia can induce immediate and delayed stimulation of ACTH and TSH synthesis and secretion. Bioelectromagnetics

Significant differences in oxidative stress in the brain of 3-month-old gerbils submitted to 10-min global cerebral ischemia and continuously exposed to ELF-MF (50 Hz, 0.5 mT) for 7 days.

<p>Measures are performed on the 7^th (immediate effect of ELF-MF) and 14^th day after reperfusion (delayed effect of ELF-MF).</p><p>Cx – Forebrain cortex; S – Striatum; Hipp – Hippocampus.</p><p>*p<0.05, **p<0.01 and ***p<0.001 (one-way analysis of variance followed by LSD test).</p

The effects of prenatal dexamethasone exposure and fructose challenge on pituitary-adrenocortical activity and anxiety-like behavior in female offspring

Prenatal glucocorticoid overexposure could largely influence pituitary-adrenal activity and anxiety-like behavior in offspring. Our aim was to study the possible potentiating effect of moderate dose of fructose – common ingredient of today’s diet – on prenatal glucocorticoid treatment-induced hypothalamo-pituitary-adrenal (HPA) axis changes. Pregnant female rats were treated with multiple dexamethasone (Dx) doses (3 x 0.5 mg/kg/b.m. Dx; 16th-18th gestational day). Half of female offspring from control and Dx treated dams were supplemented with 10% fructose solution, from weaning till adulthood. Immunohistochemistry, unbiased stereological evaluation and hormonal analysis are used to provide the morpho-functional state of pituitary and adrenal gland. Anxiety-like behavior was assessed using the light/dark box test and the elevated plus maze test. Prenatally Dx exposed females, with or without fructose consumption, had markedly reduced adrenocortical volume (p < 0.05) comparing to controls. Increased basal plasma ACTH level in these females (p < 0.05) maintained corticosterone concentration at control level produced by smaller adrenal glands. In parallel, anxiety-like behavior was shown by both tests used. In conclusion, prenatal Dx exposure cause negative psychophysiological outcome reflected in increased HPA axis activity and anxiety behavior in female offspring, while moderately increased fructose consumption failed to evoke any alteration or to potentiate effects of prenatal Dx exposure.This is the peer reviewed version of the following article: Manojlović-Stojanoski M, Nestorović N, Petković B, Balind SR, Ristić N, Trifunović S, Ajdžanović V, Filipović B, Šošić-Jurjević B, Milošević V. The effects of prenatal dexamethasone exposure and fructose challenge on pituitary-adrenocortical activity and anxiety-like behavior in female offspring. Tissue Cell. 2020;62:101309. [https://doi.org/10.1016/j.tice.2019.101309