Uticaj elektromagnetnog polja (0,5 mT, 50 Hz) na motorno ponašanje, parametre oksidativnog stresa i morfološke karakteristike mozga nakon eksperimentalno izazvane moždane ishemije na modelu pustinjskog miša
Influence of electromagnetic field (0,5mT, 50 Hz) on motor behaviour, oxidative stress parameters and morphological characteristicsof brain after global cerebral ischemia in mongolian gerbils
2012
Authors:
Rauš Balind, SnežanaContributors
Radenović, LidijaPetković, Branka
Selaković, Vesna
Prolić, Zlatko
Manojlović-Stojanoski, Milica
Document Type:
Doctoral thesis (Published version)
Metadata
Show full item recordAbstract:
Nowadays, one of the most common diseases, which affect the whole
society, is brain stroke, which can be caused by cerebral ischemia. Beside high
mortality rate, consequences of brain stroke are often permanent without
appropriate treatment. Another hallmark of modern society is development of
electronic industry and usage of diverse electron devices, therefore increasing
degree of pollution with “electromagnetic smog”. The increased presence of
extremely low frequency magnetic fields (ELF-MF) has attracted the interest of
many scientists to explore its effects, among others, on functional properties of
central nervous system. Based on the known facts of its action, we can propose
that this field affects development of pathophysiological events and recovery in
conditions like cerebral ischemia.
The purpose of this study was to determine whether ELF-MF (0.5 mT, 50
Hz, continuous exposue during 7 days) affects hypermotor activity of gerbils,
induced by 10-min global cerebral ischemia on the 1st, 2nd, 4th and 7th day
(immediate effect) as well as on the 14th day after reperfusion (delayed effect).
Also, on this model we examined whether applied ELF-MF affect oxidative
stress parameters, otherwise increased after cerebral ischemia, in some brain
regions on the 7th and 14th reperfusion day. Also, we examined effect of ELF-MF
on morphological changes in the most vulnerable structures of brain
(hippocampus, striatum and forebrain cortex) induced by ischemia on the 7th
and 14th reperfusion day, as well as performed quantification of this changes in
neurons and glial cells.
Animal behaviour was monitored for 60 min in the open field. It was
shown that the 10-min global cerebral ischemia per se induced a significant
motor activity increase (locomotion, stereotypy and rotations), and
consequently immobility decrease until day 4 after reperfusion, compared to
control gerbils. Exposure to ELF-MF inhibited development of ischemiainduced
motor hyperactivity during the whole period of registration, but
significantly in the first 2 days after reperfusion, when the postischemic
hyperactivity was most evident. Motor activity of these gerbils was still
significantly increased compared to control ones, but only on the 1st day after
reperfusion.
Parameters of oxidative stress (NO, O2-, SOD, ILP) were determined in
hippocampus, striatum and forebrain cortex applying biochemical assays.
Ischemia per se caused increasing of oxidative stress in all examined structures
on the 7th and also 14th reperfusion day with SOD values on the control level.
ELF-MF also increased production of free radical species on the 7th day
(immediate effect of ELF-MF) but in higher degree then ischemia, as well as,
activity of SOD. 7 days after cessation of exposure (delayed effect of ELF-MF)
measured values for all parameters were at the control levels. Ischemic gerbils
exposed to ELF-MF had increased values of parameters of oxidative stress on
the 7th reperfusion day (immediate effect of ELF-MF) but to a lesser extent than
ischemic animals or animals exposed to ELF-MF. On the 14th reperfusion day,
parameters of oxidative stress in the brain of ischemic gerbils exposed to ELFMF
were at the control levels.
Applying stereological methods, histological evaluation of changes in the
hippocampus was done determining its volume, volume density of
degenerating neurons and astrocytes, as well as the number of microglial cells
per unit area. ELF-MF per se did not induce any morphological changes in the
examined brain structures, while 10-min global cerebral ischemia led to
neuronal death, especially in CA1 region of the hippocampus, as expected.
Ischemic gerbils exposed to ELF-MF had significantly lower degree of cell loss
in the examined structure and greater response of astrocytes and microglial
cells than postischemic gerbils without exposure on the 7th day after reperfusion
(immediate effect of ELF-MF). Similar response was observed on the 14th day
after reperfusion (delayed effect of ELF-MF), however differences in measured
parameters were not significant.
Results of this study revealed that the applied ELF-MF (0.5 mT, 50 Hz)
decreased motor hyperactivity induced by the 10-min global cerebral ischemia,
via modulation of the processes that underlie this behavioural response. Also,
ELF-MF decreased oxidative stress induced by global cerebral ischemia thus
decreasing possible negative consequences which free radical species have in
the brain. Applied ELF-MF has possible neuroprotective function in the
hippocampus, the most sensitive brain structure in the model of global cerebral
ischemia, through reduction of neuronal death and activation of astrocytes and
microglial cells.
Keywords:
Cerebral ischemia; Electromagnetic field; Motor behaviour; Oxidative stress; MorphologySource:
University of Belgrade, Faculty of Biology, 2012, 1-127URI
http://eteze.bg.ac.rs/application/showtheses?thesesId=75https://fedorabg.bg.ac.rs/fedora/get/o:3473/bdef:Content/download
http://vbs.rs/scripts/cobiss?command=DISPLAY&base=70036&RID=41902351
http://nardus.mpn.gov.rs/123456789/2056
https://radar.ibiss.bg.ac.rs/handle/123456789/2412