RU2730944C1 - Method of simulating pain in labour in rats - Google Patents

Abstract

FIELD: medicine.SUBSTANCE: invention refers to medicine, namely to experimental medicine. Patient's pain is simulated by administering the rectal electrode into the rectum and fixing the electrodes on the tail root. At the first stage, a cylindrical electrode is introduced into rectal intestine, terminals are connected on an electric stimulator and a rectal electrode is connected, to which a signal is applied for one minute, the fact of achieving visceral pain by vegetative and behavioural reactions of the rat is stated. At the second stage, four minutes after the first, two clamp electrodes are fixed on rat tail root at distance of 10 mm from each other, pair of wires is connected in turns from electrodes of clamp type, pain irritation is applied for one minute and fixed somatic pain by vegetative and behavioural rat responses.EFFECT: method enables creating a model of birth pain in rats, followed by investigation of lysozyme activity.1 cl, 2 dwg

Description

The invention relates to medicine, namely to the study of the pathogenesis of pain during childbirth. The present invention presents a model of the formation of binary pain in rats, which serves as a guide for preparing women for childbirth.

To date, the pathogenesis of pain during childbirth is well studied. Labor pain is inherently visceral and somatic. Its nature depends on the period of childbirth and the substrate of irritation.

In the first stage of labor, pain can be classified as visceral pain, since its source is the nociceptors of the uterus. When the intrauterine pressure is reached during the period of contractions of a certain threshold value, the receptors are excited. It is believed that the receptors of the cervix are most interested in the generation of pain impulses.

In the second stage of labor, due to stretching of the vaginal walls, the somatic nerves coming from the sacral segments S2-4 are involved in the process. Afferentation passes through ∆ type fibers and type C polymodal fibers.

The model of pain formation according to the claimed invention is similar in nature to physiological labor pain in humans. It follows the stages of pain formation during childbirth.

The objective of the invention is the psycho-preventive preparation of women for childbirth. The task is achieved by modeling labor pain in rats and studying the activity of lysozyme as one of the factors of innate immunity. The technical result is the creation of a model of the formation of labor pain in rats, including the study of lysozyme activity for subsequent extrapolation of the results to humans.

The invention is illustrated by the figures, which depict:

in fig. 1 - scheme of application of an algogenic effect on test rats,

in fig. 2 - dynamics of changes in lysozyme activity in the tested rats.

Female rats on the eve of childbirth (on the 19-20th day of embryonic development of the fetus) are selected as the object of the study.

Equipment used to implement the claimed method:

- container for fixing the rat,

- two electrodes of the "clamp" type for applying painful stimulation to the receptor zone of the rat tail, to each of which a thin stranded wire in fluoroplastic insulation (MHTP) is soldered,

- a cylindrical electrode with a diameter of 4 mm, consisting of two fragments. The first fragment, 3 mm long, is separated from the second fragment by a dielectric. Has a length of 25 mm. Flexible stranded copper wire in fluoroplastic insulation is passed through the cylindrical part of the electrode and soldered to the first (end) fragment of the electrode. The second is soldered to the cylindrical part of the electrode;

- on the opposite side of each wire, a terminal is soldered for connection with an electrostimulator.

The essence of the method is illustrated by the diagram shown in FIG. 1 and is as follows.

On the eve of delivery, the rat is placed in a cylindrical container in order to protect the experimenter from the aggressive behavior of the animal and to facilitate manipulation with it.

At the first stage, a cylindrical electrode is inserted into the rectum of the test animal. Next, connect the terminals on the electrostimulator, connecting the rectal electrode. Within one minute, a stimulus is applied to the rectal electrode. The fact of achievement of visceral pain of the third or fourth degree of intensity (according to Waldman's criteria) is recorded. The rectal electrode is removed from the animal. The test animal rests for four minutes.

Next, two "clamp" type electrodes are fixed to the root of the animal's tail at a distance of 10 mm from each other. Connect in turn a pair of wires from the "clamp" type electrodes and apply painful irritation for one minute. According to the vegetative and behavioral reactions, the fact of achieving somatic pain of the third - fourth degree of intensity (according to Waldman) is recorded. Then the "clamp" type electrodes are removed.

The total residence time of an animal in a cylindrical container does not exceed 6 minutes.

The experiments were carried out on animals combined in six series of experiments. Each series of experiments includes at least 10 animals. FIG. 2 is a diagram showing the changes in lysozyme activity in the above six series of animals. Gr. 1 - control group, gr. 2 - a group of animals 2 minutes after applying a pain stimulus, and also gr. 3, column 4, column 5, column 6 - after 30 minutes, after 1 hour, after 2 hours, after 3 hours of exposure, respectively.

All manipulations with experimental animals were carried out in accordance with the Order of the Ministry of Health and Social Development of the Russian Federation No. 708n "On the approval of laboratory practice rules" dated August 23, 2010, as well as based on Directive 2010/63 / EU of the European Parliament and the Council of the European Union from September 22, 2010 on the protection of animals used for scientific purposes and Guide for the care and use of laboratory animals. National Academy - Washington, D.C. 1996.

After the end of the algogenic effect within the above-mentioned terms, the material is taken and the activity of lysozyme is examined in it. In the diagram in FIG. 2, it can be seen that the lysozyme level increases in the test rats upon pain stimulation. The activity of lysozyme is one of the humoral factors of innate immunity, which is common in almost all body fluids, and has bactericidal activity. This helps a pregnant woman to realize that an increase in the level of lysozyme activity in response to the first chord of labor pain reflects an increase in the activity of innate immunity factors in general, which prevents possible complications when an infection gets into the birth canal and on the baby's skin.

Studies of the activity of lysozyme in rats as a result of the described method show the significance of the invention in relation to the preventive preparation of women for childbirth.

Claims (1)

A method for modeling pain during childbirth in rats, characterized by the introduction of a rectal electrode into the rectum and fixing the electrodes at the root of the tail, characterized in that at the first stage a cylindrical electrode is inserted into the rectum of a rat, the terminals on the electrostimulator are connected and the rectal electrode is connected to which a signal is applied within one minute, the fact of reaching visceral pain by autonomic and behavioral reactions of the rat is recorded; at the second stage, four minutes after the first, two "clamp" type electrodes are fixed on the root of the rat's tail at a distance of 10 mm from each other, pairs of wires from the "clamp" type electrodes are connected in turn, painful stimulation is applied for one minute and fixed somatic pain by autonomic and behavioral responses of the rat.

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