مقالات پذیرفته شده در هفتمین کنگره بین المللی زیست پزشکی
the effectiveness of synthesized zink/iron oxide nana composites by single-stage sol-gel method on anxiety , spatial learning and memory in rats exposed to noise stress
the effectiveness of synthesized zink/iron oxide nana composites by single-stage sol-gel method on anxiety , spatial learning and memory in rats exposed to noise stress
Introduction: Nanotechnology is one of the interdisciplinary researches that has opened a new window of wonder in the world of science and knowledge. Nanotechnology, relying on the properties of nanoparticles in the field of diagnosis and treatment, has presented a clear perspective to researchers. Interdisciplinary collaborations of scientists and researchers in convergent sciences (NBIC) including science and nanotechnology, biotechnology, information technology and cognitive science can answer many questions and human needs, including in the field of prevention and treatment, by studying the brain and its functions. Nanoparticles cause environmental pollution in various fields. Due to the high permeability of nanoparticles, they easily pass through the blood-brain barrier (BBB), so it is possible that these substances may cause unwanted side effects. On the other hand, passing these substances through the blood-brain barrier and reaching the hippocampus can have destructive or improving effects on stress, anxiety and improving learning and spatial memory, which are among the very important concepts in psychology that deal with these issues. And the discovery of its unknowns will be of great help to the development of psychological science and the improvement of strategies to strengthen memory and reduce stress and anxiety. With the first industrial revolution, the entry of noise stressors into the work environment and human life increased. With the expansion of the use of nanotechnology, it seems necessary to study the harmful or beneficial effects of nanoparticles on neuropsychological mechanisms.
Researchers of biological psychology and physiology and nanotechnology should enter this interdisciplinary field in order to be able to determine the necessary good news and warnings in the field of the use of these nanomaterials and its synergistic effects with environmental stresses on the physical and mental health of people along with the emergence of new technologies. do The aim of this study is to investigate the effect of exposure to noise pollution caused by traffic in rats on the neuronal activity of this area of their hippocampus and its effect on anxiety, learning and spatial memory along with the administration of zinc/iron oxide nanocomposites, which according to our studies, so far No research has been done in the field.
With the first industrial revolution, the entry of sound stressors into the working environment and human life increased, and with the expansion of the use of nanotechnology, studying the harmful or beneficial effects of nanoparticles on neuropsychological mechanisms seems necessary. Researchers of biological psychology and physiology and nanotechnology should enter this interdisciplinary field in order to be able to determine the necessary good news and warnings in the field of the use of these nanomaterials and its synergistic effects with environmental stresses on the physical and mental health of people along with the emergence of new technologies. do The aim of this study is to investigate the effect of exposure to noise pollution caused by traffic in rats on the neuronal activity of this area of their hippocampus and its effect on anxiety, learning, and spatial memory along with the administration of zinc/iron oxide nanocomposites, which according to our studies, so far No research has been done in the field. The mechanism of LTP in the hippocampus region can be evaluated and investigated as the most important region involved in memory formation and learning.
Methods: In this research, the effectiveness of zinc/iron oxide nanocomposites on anxiety, learning, and spatial memory in rats exposed to sound stress was investigated. First, zinc/iron oxide nanocomposites were prepared by the one-step sol-gel method. Then, it was characterized using SEM and transmission electron microscope, as well as XRD. In the continuation of this study, 8 groups and each group with 10 mice included, control group, stress group, control groups receiving nano including three doses of zinc/iron oxide nanocomposites (5, 2.5, 1.25 mg/kg) and The groups receiving nano stress which included three doses of nanocomposite were investigated. After 15 days, in order to investigate anxiety, learning and spatial memory, elevated plus maze test, Morris blue maze and electrophysiological recording of the Schafer collaterals pathway of the hippocampus were used. The results show that zinc/iron oxide nanocomposites did not have an ameliorating effect on anxiety in the elevated plus maze test and did not affect learning in the Morris blue maze test and did not have a positive effect on the animals' memory in the probe phase. On the other hand, the injection of zinc/iron oxide nanocomposite to the animals subjected to sound stress improved the induction of LTP in them, while the injection of nanocomposite had a negative effect on the induction of LTP in the animals of the control group. Determining the exact mechanism of the effect of zinc/iron oxide nanocomposite on improving or destroying memory requires additional tests.
In this study, 80 adult male Wistar rats weighing about 220-250 grams were used, which were randomly divided into 8 groups of 10. The animals were kept in the animal house with an approximate temperature of 25°C and a humidity level of 55%, under conditions of 12 hours of darkness and 12 hours of light, and they had easy access to standard food and water. The sampling method was performed as a simple random one-step method.
The studied groups are as follows:
1- The control group that does not receive zinc/iron oxide nanocomposite and does not face noise pollution (CO).
2- The group of rats that received zinc/iron oxide nanocomposite in the amount of (5 mg/kg) for 12 days but did not face noise pollution (CO+N5).
3- The group of rats that received zinc/iron oxide nanocomposite in the amount of (5.2 mg/kg) for 12 days but did not face noise pollution (CO+N2.5).
4- The group of rats that received zinc/iron oxide nanocomposite in the amount of (25.1 mg/kg) for 12 days but did not face noise pollution (CO+N1.25).
5- Stress group; Rats exposed to noise pollution for 2 hours between 8:00 AM and 12:00 PM for 12 days and received normal saline (ST).
6- Rats are exposed to noise pollution for 2 hours between 8 am and 12 noon for 12 days and receive zinc/iron oxide nanocomposite in the amount of (5 mg/kg) from the beginning of stress to conducting electrophysiology tests. (ST+N5).
7- Rats are exposed to noise pollution for 2 hours between 8:00 AM and 12:00 PM for 12 days, and receive zinc/iron oxide nanocomposite in the amount of (5.2 mg/kg) from the beginning of the stress to the electrophysiology tests. ST+N2.5).
8- Rats are exposed to noise pollution for 2 hours between 8:00 AM and 12:00 PM for 12 days, and receive zinc/iron oxide nanocomposite in the amount of (25.1 mg/kg) from the beginning of the stress to the electrophysiology tests. ST+N1.25).
"The single-stage sol-gel method for nanocomposites is a versatile and efficient chemical process employed to fabricate nanomaterial-based composite systems. In this method, a precursor solution (sol) containing metal or metal oxide precursors, organic or inorganic additives, and a solvent is subjected to controlled hydrolysis and condensation reactions. These reactions result in the formation of a homogeneous nanocomposite material wherein the nanoparticles (typically in the nanometer range) are uniformly dispersed within a matrix. The single-stage approach distinguishes itself by consolidating precursor preparation, nanoparticle formation, and matrix development into a single reaction step, offering advantages such as precise control over nanoparticle size and distribution, tailoring of material properties, and scalability for various applications in fields such as catalysis, electronics, optics, and energy storage."
Results: One of the ways to check the level of anxiety in different experimental groups is the plus high maze. As explained in the materials and methods chapter, it can be said that the fewer times the animals enter the open arms of the maze or the less time they spend in them, the higher their anxiety level. The analysis of the data obtained from this experiment as well as the time spent by the animal in the open arm showed that the exposure of the animals to sound stress led to anxiety behavior in them, so that the animals of the stress group had a significantly longer time than the control group. They spent less time in the open arm. On the other hand, the injection of all three doses of zinc/iron oxide nanocomposites to the animals of the control group receiving nano caused anxiety behavior in them. Also, the injection of all three doses of zinc/iron oxide nanocomposites did not have any effect on improving the behavior of animals in the stress group receiving nano.
• The results of this part of the study showed that there is no significant difference in learning and memory between the two control groups and the stress group and the control group receiving nanocomposite and the stress group receiving nano.
• Disruption in learning and spatial memory is due to disruption of the HPA axis, and finally, this inefficiency can cause a decrease in granule neurons and neurogenesis in the hippocampus.
• Hippocampal glucocorticoid receptors are very sensitive to increased amounts of these hormones, and high amounts of these hormones cause damage to neurons in this area of the brain.
Also, in the investigation of the effect of zinc metal on learning and spatial memory, it was stated in a study that food supplements containing iron and zinc improve learning and spatial memory and also have a significant effect on motor activity.
• Severe zinc deficiency in adult mice causes damage to the hippocampus and affects its function. So that memory damage was widely observed along with zinc deficiencies.
• It was also shown that young and old mice with zinc deficiency have poorer spatial memory. Zinc oxide nanoparticles lead to cytotoxicity through the production of reactive oxygen species, oxidative damage, stimulation of inflammation and cell death.
• Exposure to zinc vapor may have negative effects on cognition and memory, which are age- and gender-dependent. Due to the contradictory effects of nano zinc oxide in behavioral tests related to cognitive processes, memory and learning, it is difficult to identify the mechanism of their effect.
Examining the data obtained from the training sessions for animals in the Morris water maze, shows that the studied animals gradually recognized the location of the hidden platform by using the spatial keys in the laboratory and also by the placement of the operator and at the same time as the number of trials increased. They spend less time to find the hidden platform and therefore travel less distance.
It shows that the injection of all three doses of zinc/iron oxide nanocomposites had no effect on improving the memory of animals subjected to sound stress. Meanwhile, the injection of all three doses of zinc/iron oxide nanocomposites caused memory disorders in controlled animals.
The results of graph (4-6) show that the injection of all three doses of zinc/iron oxide nanocomposites had no effect on improving the memory of animals subjected to sound stress. On the other hand, the injection of all three doses of zinc/iron oxide nanocomposites caused memory impairment in controlled animals.
Conclusion: In general, the current research shows:
A) Zinc/iron oxide nanocomposites were prepared by the green method and using the modified sol-gel technique.
b) Exposure of animals to sound stress caused an increase in their anxiety level.
c) In the stress group receiving nano, injection of all three doses of nanocomposite did not reduce anxiety behavior in animals.
d) In the three-dose injection stress group, zinc/iron oxide nanocomposite had no effect on improving the learning process of animals.
e) Sound stress caused disturbances in the spatial memory of animals, and the injection of all three doses of nanocomposite did not improve spatial memory in animals exposed to stress.
f) Sound stress did not induce LTP in animals.
g) Injection of nanocomposite to animals exposed to sound stress-induced LTP.
Discussion and conclusion about the effectiveness of zinc/iron oxide nanocomposites prepared by the green method, there is a difference on the anxiety of rats exposed to sound stress and rats with and without exposure to sound stress.
The findings of this part of the study show the destructive effect of sound stress on the anxious behavior of rats. By stimulating the hypothalamus-pituitary-adrenal (HPA) pathway, stress causes the release of cortisol hormones in humans and corticosterone in rodents, which by activating the sympathetic system increases the plasma concentration of norepinephrine hormones. Long-term exposure to sound waves leads to physiological and psychological damage that increases oxidative stress. The findings of this section are in line with most previous studies, including the studies of Ahmadi et al. (2017) and Karimi et al. (2015).
suggestions
According to the positive results of this research, which indicated the significant effect of zinc/iron oxide nanocomposites injection on hippocampus neuronal responses in rats, it is suggested to use this method in investigating the effects of other nanoparticles.