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MORPHOLOGY OF THE CHOROID PLEXUS OF THE BRAIN OF RATS
UNDER VARIOUS METHODS OF EUTHANASIA
Dekhkanova N.T.
Dekhkanova Nilufar Tashpulatovna – senior lecturer
Department of Histology, Cytology and Embryology,
Samarkand State Medical University
Samarkand, Republic of Uzbekistan
https://doi.org/10.5281/zenodo.13309034
Annotation.
The comparative morphology of the choroid plexus of the
ventricles of the brain of rats was studied during euthanasia with an overdose of
anesthesia and during euthanasia by acute experimental blood loss by
transection of the carotid artery and abdominal aorta. It has been established
that during euthanasia by an overdose of anesthesia, the plexus vessels are
located compactly, and during euthanasia by blood loss they diverge. These
phenomena during transection of the carotid artery are more obvious in
comparison with those with transection of the abdominal aorta.
Key words
: choroid plexus of cerebral ventricles, comparative
morphology in experiment
Relevance.
The soft consistency of the brain substance and its location in
a limited space inside the skull requires reliable protection from mechanical
influences. Therefore, nature has created a liquid hydration and shock-
absorbing system around it, represented by cerebrospinal fluid, which is
produced by the choroid plexus of the ventricles of the brain. This fluid fills the
subarachnoid space of the brain and spinal cord, the ventricles of the brain and
the central canal of the spinal cord. The production, renewal, and therefore
circulation of this fluid is directly related to the blood. Therefore, changes in
blood supply and pressure in the vascular system of the brain are reflected in
the pressure and volume of this fluid in the cavities of the ventricles of the brain.
Scientific works devoted to the study of the choroid plexus of humans [1,4] and
laboratory animals [2,3] are available. Often in morphological experimental
studies, euthanasia (killing) of laboratory animals by bloodletting is used.
Naturally, this also leads to bleeding of the brain vessels, and therefore the
choroid plexus of its ventricles. But with euthanasia by overdose of anesthesia,
this does not happen. The issue of comparative study of the morphology of the
choroid plexus in one or another method of euthanasia is one of the
insufficiently studied. From this point of view, studying the morphology of the
choroid plexus of the ventricles of the brain, which is a producer of
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cerebrospinal fluid, in various methods of euthanasia is one of the pressing
issues.
Objective of the work:
To study the morphology of the choroid plexuses of the
ventricles of the brain of rats during euthanasia by bloodletting and anesthesia
overdose
Material and research methods.
The choroid plexus of the ventricles of the
brain was studied in 16 rats: 8 rats after euthanasia from acute experimental
blood loss (by transection of the carotid artery in 4 rats, and by transection of
the abdominal aorta in 4 rats), 8 rats after euthanasia by an overdose of
anesthesia. Euthanasia of rats was carried out in compliance with all bioethical
requirements and under anesthesia. The brain is fixed in 12% neutral formalin
and completely embedded in paraffin. Histological processing of the material
was carried out according to generally accepted methods. Relatively thick
histotopographic sections of the brain were stained with hematoxylin–eosin and
Nissl thionin.
Research results.
In rats that were euthanized by an overdose of anesthesia,
the choroid plexus of the ventricles of the brain is represented by densely
packed vessels (Fig. 1A). The free space between the plexus vessels is
insignificant and is visible in the form of a light layer of various configurations
A
Б
Fig.1. Choroid plexus of the ventricle of the rat brain, during euthanasia by
anesthesia overdose (A) and acute blood loss (B) due to transection of the
abdominal aorta. Staining using hematoxylin-eosin method. About. 20,
approx. 7.
As can be seen from the figure, the plexus vessels having almost the same caliber
are located close to each other and the main vessel, apparently supplying blood
to the plexus vessels, is quite large. caliber. And this vessel is also full-blooded.
During euthanasia of acute blood loss, the choroid plexus has the appearance of
a branchy tree (Fig. 1B). The vessels move away from each other and the space
between them expands. In this case, you can notice. that from the main vessel
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begins the anchor blood vessel, which branches out to form a plexus and they
are all connected to each other and to the branches of the anchor vessel. We
observed a similar picture when comparing choroid plexus preparations during
transection of the carotid artery during euthanasia of anesthesia overdose.
Moreover, during euthanasia by an overdose of anesthesia, the location of the
plexus vessels is also more compact (Fig. 2A), and during euthanasia by blood
loss, the vessels diverge (Fig. 2B). It should be noted that with euthanasia with
transection of the carotid artery, the picture of vascular divergence is more
demonstrative. And in this case, the main blood vessel and the anchor blood
vessel branching off from it forming the choroid plexus are also visible.
А
Б
Fig.2. Choroid plexus of the 4th ventricle of the rat brain during euthanasia
by an overdose of anesthesia (A) and during euthanasia by acute blood loss
by transection of the carotid artery. Nissl thionin staining. Vol.20, 0k 7.
Thus, in rats euthanized by bloodletting, the blood vessels of the ventricular
plexus fan out. Free space appears between the plexus vessels. And the anchor
blood vessel, due to the branching that forms the choroid plexus of the
ventricles, is directly connected to the collector blood vessel. During euthanasia
with an overdose of anesthesia, the plexus vessels are located compactly around
the collector blood vessel.
Conclusions:
The results of our research suggest that there is a balance of
volume and pressure between the circulatory and liquor systems of the brain.
During euthanasia by an overdose of anesthesia, the plexus vessels are located
more compactly, and during euthanasia by bloodletting they diverge.
Apparently, acute blood loss leads to bleeding of the vessels of the plexus of the
ventricles of the brain and they seem to “float up” in their cavity containing
cerebrospinal fluid. These data can serve as additional help in assessing the
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results of experimental studies on the morphology of cerebrospinal fluid
producers.
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