RU2638270C2 - Method for prevention of neurological status and muscular tonus violations in acute radiation disease in experiment - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: to prevent psychoneurological disturbances in an animal experiment after single uneven proton irradiation at doses capable of causing acute radiation disease, Semax preparation 0.1% nasal drops is administered intranasally. Semax is injected 1 drop into each nostril three times a day from 1 to 7 days after exposure to radiation.

EFFECT: method allows to maintain a normal level of the orienting-research reaction, emotional status, the relationship between the excitation and inhibition processes of the central nervous system and muscle tone, disturbed by proton irradiation.

2 ex, 1 tbl

Description

The invention relates to experimental medicine and may find application in astronautics to maintain a high level of operator activity of astronauts under conditions of unforeseen exposure to radiation, as well as rehabilitation of patients after proton therapy of brain tumors.

Experimentally proven damage to the central nervous system (CNS) by corpuscular ionizing radiation is the main risk factor for the health of astronauts during interplanetary flights [1].

The medical product under the trade name "Semax" has a chemical name: methionyl-glutamyl-histidyl-phenylalanyl-prolyl-glycyl-proline. Semax belongs to the pharmaceutical group: nootropic agent and is available in dosage form: nasal drops 0.1% [2]. The drug affects the processes associated with the formation of memory and learning, strengthens attention during training and analysis of information, improves the consolidation of the memorial trail in patients after neurosurgical interventions, traumatic brain injury, suffering from cerebrovascular diseases, including discirculatory encephalopathy, improves the body's adaptation to hypoxia cerebral ischemia, anesthesia and other damaging effects [3]. It has been established that Semax provides increased mental performance in combat athletes [4]. It is known that Semax in the composition of various pharmacological compositions increases resistance to hypoxia and has neuroprotective and antiamnestic activity in experimental animals with a single intraperitoneal administration [5, 6].

Separate sources of information have been found in the literature database that describe the use of Semax as part of complex therapy for elderly patients who had a long history (several years) of contact with ionizing radiation without specifying a radiation dose or transferred radiation sickness. Against the background of complex therapy and taking Semax at a dose of 5000 mcg per day for 7 days in patients 7 years after participating in the aftermath of the Chernobyl accident, there was a disappearance of lethargy, a decrease in mental and physical fatigue, an improvement in mood, attention, memory, and mental operability [3].

The positive effect of Semax on the hemodynamics of the brain, on the work of the heart, on mental performance and other indicators of psychophysiological status was noted during the rehabilitation of veterans of special risk units 20-40 years after participating in the elimination of radiation accidents [7]. At the same time, the authors indicate that the personality structure of the veterans was affected not only by the effects of radiation stress, but also by the psychological consequences of the economic crisis in the country.

As part of complex therapy, Semax had a positive effect on the mental health of representatives of the population 35 years after exposure to the Teche River and the East Ural radioactive trail [8]. Doses of chronic exposure ranged from 0.02 to 1.3 Gy. Moreover, the author rightly notes the possibility of influencing the mental health of the population of the affected areas to a much greater extent of socio-economic factors, such as alcoholism, and not radiation. Thus, no sources of information on the effect of Semax on the neuropsychiatric status in acute radiation sickness were found in the literature database.

The objective of the study is to investigate and prove the possibility of optimal prophylactic use of the official drug Semax nasal drops after radiation exposure in doses that cause acute radiation sickness, to restore to a normal level of neuropsychiatric status.

The prophylactic administration of Semax to irradiated animals makes it possible to normalize indicators of neuropsychiatric status, such as an orientation-research reaction, emotional status, disturbed by radiation, during the experiment.

The technical result is to maintain a practically normal level: an increase in emotional status (ES) and a decrease in the orientational research reaction (OIR), as well as the ratio of the processes of excitation and inhibition (OIR / ES) in the central nervous system, indicators of the neuropsychiatric status with proton radiation.

To achieve this goal, the influence of Semax on the spontaneous motor activity of irradiated mice in the "Open Field" was studied.

The study revealed that the anti-radiation effects are achieved when using Semax in the produced dosage form as nasal drops.

We have found that Semax is able to exert a radioprotective effect in terms of neuropsychiatric status on animals exposed to acute radiation during the height of radiation injury.

In the experiments used Semax official drug. Registration number: LS - 002553. Chemical name: methionyl-glutamyl-histidyl-phenylalanyl-prolyl-glycyl-proline. Dosage form: nasal drops 0.1%.

Semax prophylactic efficacy was studied in 102 outbred ICR CD-1 SPF mice, females weighing 21-25 g and 22-29 g in two different experiments. In the experiments, only clinically healthy individuals were selected. Groups: control without irradiation, control with irradiation and experimental, were formed by a random choice of animals of equal mass.

The test of the prophylactic effectiveness of Semax was performed with proton irregular irradiation of mice in the medical beam of the JINR phasotron. Mice were fixed and irradiated in special individual containers of 4 animals at a time. The direction of the proton beam is craniocaudal.

The average energy of the proton beam at the entrance to the cabin in front of the moderator is 171 MeV. The beam energy in the cabin was determined by the range of the beam in water (R = 200 mm of water). The measurements were carried out by a semiconductor silicon detector. The average value of LET at the beam input dE / dx = 0.49 keV / μm.

Dosimetric calibration of the beam at each point of the deep dose distribution was carried out by the PT300 UNIDOS-E clinical dosimeter TM30013 ionization chamber.

Irradiation was carried out in a natural Bragg peak with an additional moderator thickness of 190 mm. In this case, the head of the mouse was irradiated at the maximum dose, the beam practically did not reach the tail of the mouse body, stopping in the front of the body. The dose rate at the beam inlet (with the additional moderator removed) was 0.62 Gy / min; the dose rate at the irradiation point (90% of the dose level at the Bragg peak) was 1.42 Gy / min. The ratio of dose at the point of exposure to the dose at the entrance of 2.28.

The objects were irradiated in doses at the input of 1.0 and 1.25 Gy, and this was 2.28 and 2.85 Gy at the point of irradiation, i.e. on the head area. To control the exposure of containers with mice, a radiochromic film was exposed.

Control animals — the biocontrol group — were placed in the container only without irradiation.

Semax was introduced into the mice of the main group dropwise into each nostril, starting from the second hour after the end of irradiation, three times a day in the morning, afternoon and evening for 7 days. The effective dose of Semax for mice is determined by conversion to the surface of the body [9], based on the effective dose for humans, known from the instructions [2]. Control irradiated animals were injected with chilled boiled water.

The experiments were carried out in compliance with the "Rules for the use of experimental animals", regulated by order of the Ministry of Health of the USSR No. 75 of 08/12/1987

The influence of Semax on the neuropsychiatric status of irradiated animals was evaluated by the level of locomotor activity in the Open Field [10]. On a gray circular installation “Open Field”, with a diameter of 63 cm, with 13 holes and 18 sectors, for 3 minutes the intersection of sectors, passages through the center, vertical lifts, grooming, mink reflex, fading, and movement in place were taken into account. The level of orientational research reaction (OIR) was defined as the sum of acts of intersection of sectors, passage through the center, rise and mink reflex. Emotional status (ES) was determined by the sum of the acts of indicators such as grooming, fading, movement in place. To assess the ratio of the processes of excitation and inhibition in the central nervous system, the ratio of the OIR indicator to the ES indicator was determined [11].

Statistical processing of the data obtained in the experiments was carried out using generally accepted methods of variation statistics. Arithmetic mean values and their standard errors were calculated. The statistical significance of differences in animals of the compared groups was judged by the criteria of Student and Mann-Whitney.

The effect of Semax on the neuropsychiatric status of mice irradiated with protons is shown in Table 1.

As can be seen in table 1, proton irradiation causes a violation of the neuropsychiatric status of mice, expressed in a statistically significant decrease in ES and an increase in the OIR / ES ratio (experiment No. 1 and 2) compared with unirradiated control. The increase in OIR after irradiation was not statistically significant. The introduction of the Semax preparation to trained animals led to the maintenance of a practically normal ES level and a statistically significant decrease in the ratio of the processes of excitation and inhibition (OIR / ES) to the normal level in both experiments and a decrease in the radiation stimulated rate in experiment No. 2.

Note:

1 - Statistically significant differences with group No. 5 (Mann-Whitney test, P <0.05);

2 - Statistically significant differences with groups No. 1 and 3 (Mann-Whitney test, p <0.05);

3 - Statistically significant differences with groups No. 4 and 6 (Mann-Whitney test, p <0.05).

An analysis of the totality of the results allows us to conclude that Semax has a prophylactic radioprotective effect upon intranasal administration after radiation exposure. On the model of the bone marrow form of acute radiation sickness that developed after proton irradiation of mice, it was shown that the use of Semax reduces the negative impact of radiation on indicators of neuropsychiatric status.

Thus, the proposed method is as follows.

Immediately after irradiation, the animals are intranasally administered with a solution of the peptide: methionyl-glutamyl-histidyl-phenylalanyl-prolyl-glycyl-proline. Moreover, they use the official drug Semax - nasal drops 0.1%. The drug is used in mice after a single acute exposure, which can cause acute radiation sickness. The drug Semax is used from 1 to 7 days after irradiation daily by intranasal administration three times a day.

Example No. 1

Semax antiradiation effect is studied in an experiment on 22 outbred ICR CD-1 mice weighing 21-25 g, which are in vivarium on a normal diet.

A single exposure to a proton beam at the JINR phasotron with an initial energy of 171 MeV is used as a model of radiation damage. Mice were irradiated in individual containers in a craniocaudal direction in 4 animals at a time. The dose rate at the inlet is 0.62 Gy / min, at the point of irradiation (head area) 1.42 Gy / min. The dose at the entrance of 1.0 Gy in the head region was 2.28 Gy. After irradiation, animals are divided into two groups of mass equivalent, one of them - the main one - receives the drug Semax 0.1%, 1 drop in each nostril, starting from the second hour after irradiation, three times a day in the morning, afternoon and evening for 7 days . Control irradiated animals are injected with boiled chilled water. In addition, to assess the damaging effects of radiation compared with intact animals, a biocontrol group was formed - non-irradiated animals. The effect of irradiation and Semax on the neuropsychiatric status of animals on the 7th day after irradiation was evaluated by the level of locomotor activity in the Open Field [8] with a circular gray arena with a diameter of 63 cm. For 3 minutes, intersection of sectors, passage through the center, elevation, and mink reflex were taken into account - the sum of these tests was an indicator of OIR - an orientational research reaction, and the grooming, fading, and motion tests are an indicator of emotional status.

The grooming rate in irradiated animals without Semax use averaged 0.3 ± 0.2 acts per 3 minutes of observation and turned out to be statistically significant (Mann-Whitney test, p <0.05) lower than 0.9 ± 0 biocontrol, 2 acts, while the indicator in animals protected by Semax with the introduction of Semax 0.7 ± 0.2 acts did not statistically significantly differ from the value in biocontrol. The total ES value in biocontrol was 4.4 ± 0.5 acts, in irradiated unprotected (with the introduction of boiled water) - 1.6 ± 0.2 acts, and in those irradiated with the introduction of Semax, it recovered to 3.0 ± 0.45 acts . The differences between the control and the main groups of irradiated animals are statistically significant (Mann-Whitney test, p <0.05). Proton irradiation at a dose of 2.28 Gy per head region caused a statistically significant increase in the OIR / ES ratio from 38.97 ± 6.02 in unirradiated animals to 101.0 ± 11.84, in irradiated animals treated with boiled water. The administration of Semax to irradiated animals was statistically significant, almost two times, reduced the level of this indicator to 52.49 ± 5.1, bringing it closer to the value in unirradiated animals - 38.97 ± 6.02.

Thus, the prophylactic radioprotective effect of Semax on the level of neuropsychiatric status manifested itself in maintaining, upon exposure, the ES and the ratio of the processes of excitation and inhibition (OIR / ES), almost at the normal level.

Example No. 2

Semax antiradiation effect is studied in an experiment on 26 outbred ICR CD-1 mice weighing 22-29 g, under vivarium conditions on a normal diet.

A single exposure to a proton beam at the JINR phasotron with an initial energy of 171 MeV is used as a model of radiation damage. Mice were irradiated in individual containers in a craniocaudal direction in 4 animals at a time. The dose rate at the inlet is 0.62 Gy / min, at the point of irradiation (head area) 1.42 Gy / min. The radiation dose at the entrance was 1.25 Gy, in the head region - 2.85 Gy. Biocontrol are non-irradiated animals. After irradiation, animals are divided into two groups of mass equivalent, one of them, the main one, receives the drug Semax 0.1%, 1 drop in each nostril, starting from the second hour after irradiation, three times a day in the morning, afternoon and evening for 7 days . Control irradiated animals are injected with boiled chilled water. The effect of irradiation and Semax on the neuropsychiatric status of animals on the 7th day after irradiation was evaluated by the level of locomotor activity in the Open Field [8] with a circular gray arena with a diameter of 63 cm. Within 3 minutes, acts of intersection of sectors, passages through the center, rise, and mink were taken into account reflex - the sum of these acts was an indicator of OIR - an orientational research reaction, and acts of grooming, fading, movement in place - an indicator of emotional status (ES). The neuropsychiatric status of mice was evaluated on the 7th day after irradiation.

The RIR indicator in the biocontrol group amounted to 136.3 ± 14.2 acts, in the group irradiated with boiled water 141.5 ± 14.2 acts, and in the group irradiated with Semax 127.2 ± 5 acts, with statistically significant differences marked between the main and control groups of irradiated animals (Mann-Whitney test, p <0.05). Those. training with protons at a dose of 2.82 Gy increased the OIR indicator, and the introduction of Semax led to its preservation almost at a normal level.

ES in the biocontrol group amounted to 8.9 ± 1.6 acts, in the group of irradiated controls - 4.7 ± 0.2 acts, and in the group of irradiated with the introduction of Semax 7.2 ± 0.4 acts, with statistically significant differences marked between the main and control groups of irradiated animals (Mann-Whitney test, p <0.05).

Irradiation with protons at a dose of 2.85 Gy per head region caused a statistically significant increase in the OIR / ES ratio from 20.88 ± 1.41 in unirradiated animals to 30.76 ± 2.67 in irradiated animals that received boiled water. The introduction of Semax to irradiated animals statistically significantly kept the level of this indicator 18.06 ± 1.29, in fact, at the level in non-irradiated animals.

Thus, in the model of acute radiation sickness, the preventive radioprotective effect of Semask in terms of neuropsychiatric status manifested itself in maintaining, when exposed to ES, the ORR index and the ORR / ES ratio, at practically normal levels.

The effect is achieved with a course of intranasal administration of Semax 0.1% intranasal drops within 7 days after irradiation.

The indicated prophylactic radioprotective properties of Semax allow it to be used to solve the problems of radiation medicine, in particular, to ensure the cosmonauts' operator activity during corpuscular irradiation, as well as maintaining the psychoneurological status of patients during proton therapy of oncological diseases of the central nervous system.

Sources of literature

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2. The register of medicines of Russia 2000-2016. Semax solution 0.1%. Instructions for use, contraindications and composition.

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Claims (1)

A method for the prevention of neuropsychiatric disorders developing during acute radiation sickness in an experiment, characterized in that the animal, after a single uneven proton irradiation in doses that can cause acute radiation sickness, is administered intranasally the drug Semax 0.1% nasal drop, 1 drop is administered 1 drop in each nostril three times a day from 1 to 7 days after exposure to radiation.