RU2368394C2 - Method of reducing risk of radiation cataract genesis at chronic effect of low doses of ionisation radiation - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, radiology and ophthalmology, and can be used for reducing the risk of radiation cataract genesis at chronic effect of low doses of ionisation radiation. For that purpose water with decreased content of deuterium is injected to the organism. At that, deuterium concentration can be 1 ppm to 140 ppm. Potable water with decreased deuterium concentration can be injected to the organism orally, parenterally or by installing into the eye independently or as the solvent for physiologically active substances and pharmacological preparations. Potable water with decreased deuterium concentration can be injected to the organism till chronic influence of low doses of ionisation radiation takes place, as well as during the effect of ionisation radiation and after it.

EFFECT: method allows restraining formation of phacoscotasmus, having excluded such side effects as surface keratitis, blepharitis, and pruritus.

4 cl, 2 tbl

Description

The invention relates to medicine, more specifically to radiology and ophthalmology, and can be used to reduce the risk of developing radiation cataractogenesis under chronic exposure to low doses of ionizing radiation.

One of the pressing issues of radiobiology is the search for methods to reduce the risk of developing distant radiation pathology. It is known that radioprotectors that have a protective effect in the acute period of radiation injuries, as a rule, do not significantly affect the frequency of long-term effects. From these considerations, it is natural to assume that substances acting as adaptogens that increase the nonspecific resistance of the organism could correspond to the most formulated task.

Given the high radiosensitivity of the lens, its insecurity and the absence of recovery processes from radiation disorders in it, the concern of specialists and the attention of researchers to radiation cataractogenesis issues in the long term after exposure to ionizing radiation is understandable. The relationship between the risk of cataracts and the dose of ionizing radiation of various quality has been shown [A.N. Kabachenko, 1974], as well as the possibility of the formation of lens opacities at low doses of cosmic radiation in astronauts both in the active period of their activity and in the end of their professional career. In addition, the influence of ultraviolet radiation contributes to the acceleration of the development of lens opacity, which astronauts can be affected [Rastergar, Eckart, Frocmel et al., 2000; Cucinota, Feiveson, Manuel et al., 2006; A.D. Strzhizhovsky, 1995].

During space missions carried out to date, the doses of ionizing radiation do not exceed the maximum permissible level; during long interplanetary flights, the doses of cosmic radiation can significantly increase, including as a result of emergencies associated with the flight of astronauts into outer space. Space flights currently carried out have revealed a significant number of clouding of the lens of the initial degree in American astronauts [Rastegar, Eckart, Frocmel et al., 2006; Cucinotta, Feiveson, Manuel et al., 2006].

With an increase in the range and duration of space flights, the risk of radiation exposure to the visual analyzer will increase. This leads to the need to look for additional ways of both physically protecting the eyes of the astronauts and biological methods to increase the general resistance of the body, which would not cause side effects for a long time and provide reliable protection against cosmic radiation.

As the closest prototype method of the claimed invention, we have chosen the method described in the book by MD Mashkovsky “Medicines” in the section “Drugs Used to Delay the Development of Cataracts”, 2006, Novaya Volna Publishing House, 1200 sec ., 15th edition.

To delay the development of cataracts, the pharmacological preparation KATALIN is used - sodium salt of 1-hydroxy-5-oxo 5H-pyrido- (3,2-α) -phenoxazine-3-carboxylic acid. The drug is used in the form of eye drops.

The disadvantage of this method is:

possible superficial keratitis, blepharitis, itching; with severe side effects, the use of the drug is stopped.

The technical result of the claimed invention is to eliminate the above drawback, i.e. an exception in the prevention of superficial keratitis, blepharitis, itching.

The technical result is achieved by the fact that in the known method of reducing the risk of radiation cataractogenesis under chronic exposure to low doses of ionizing radiation in mammals, including the introduction of pharmacological agents, water with a modified isotopic composition, namely with reduced concentrations of the heavy stable hydrogen isotope deuterium, is used as a preparation .

Such water can be obtained by electrolysis, rectification and other isotope fractionation methods.

The concentration of the heavy stable isotope of hydrogen - deuterium can range from 0 ppm to 140 ppm.

Drinking water with reduced concentrations of the heavy stable isotope of hydrogen - deuterium can be administered orally, parenterally or by instillation into the eye on its own or as a solvent for physiologically active substances and pharmacological preparations.

Drinking water with reduced concentrations of the heavy stable isotope of hydrogen - deuterium can be introduced into the body before chronic exposure to low doses of ionizing radiation, as well as during and after exposure to ionizing radiation.

To objectify the actual solution of the problem and achieve the technical result, the results of experiments on the effect of water with a reduced deuterium content on the long-term effects of ionizing radiation are presented below, in which the frequency of post-radiation opacification of the lens in small laboratory animals was studied.

Male mice of the F1 line (CBAXC57B16) were irradiated daily at a dose of 12.5 cGy to obtain a total dose of 0.25; 0.5 and 1.0 Gy (table 1). After irradiation, the lenses of animals were examined 1 time per month. There were 20 animals in each group. A group of animals irradiated with a total dose of 1.0 Gy was given water with a reduced deuterium content for 2 months before irradiation and during the observation period. Control animals were kept in plain tap water throughout the experiment. Before irradiation and regularly after irradiation, the animals were examined with an electrophthalmoscope and a magnifier of +15.0 D. The pupils were dilated with a 1% solution of gomatropin. The frequency and timing of opacification of the lens of the initial stage, as well as the dynamics of their maturation, depending on the dose of gamma radiation and the duration of the post-radiation period, were taken into account. The frequency of lens opacities was determined as a percentage of the number of eyes with opacities of the lens to the number of eyes examined in each group of experimental animals. The obtained data were compared with the results of similar observations in the group of unirradiated mice. Assessment of lens opacities was performed on a 4-point scale proposed for small laboratory animals [K.W. Christenberry and Y. Furth, 1951]. With minor modifications, this technique has been applied to date. According to this technique, the early signs of cataracts, the 1st stage of the lens opacification, appear as separate vacuoles under the posterior lens capsule, and at high doses under the anterior capsule. The involvement of both (anterior and posterior) subcapsular cortical regions in the pathological process was evaluated as stage II of the lens opacification. The clouding of the lens at this stage looks like a small opaque disk on the back or front and back capsule of the lens. Stage III is characterized by the formation of a denser, stellate opacification of the lens when the fundus is poorly visible. Stage IV - complete clouding of the lens [A.N. Kabachenko, 1974, Brenner, Medvedovsky S., Huang, 1991].

The results of the studies showed that the first initial lens opacities were found under the posterior lens capsule 18 weeks after irradiation of mice at a dose of 1.0 Gy (table 2). In animals that received water with a low deuterium content and were irradiated at the same dose, the first clouding of the lens was detected only 40 weeks after irradiation. With an increase in the postradiation period, the frequency of lens opacities increased in all groups of irradiated animals; however, as can be seen from the table, in mice that received water with a low deuterium content, the frequency of lens opacities was 1.5 times lower than in animals irradiated in the same dose and contained in plain tap water. It can also be noted that cataract maturation in mice that received water with a low deuterium content occurred at a slower pace, as evidenced by the rate of clouding of the lens of the second stage (3.6% versus 5.8% after 61 weeks and 3.3% against 12.5% after 72 weeks).

85 weeks after irradiation in mice at a dose of 1.0 Gy and treated with tap water (intact animals), stage III cataract was observed in 3.1% of cases, while in animals treated with water with a low deuterium content, the development of cataract was delayed by II stages to natural death of animals, and the total relative frequency of lens opacities did not exceed it in intact animals. In animals irradiated with a dose of 0.25 Gy, the frequency of clouding of the lens of the initial stage practically did not exceed the control level (p≤0.05).

After irradiation of animals at a dose of 0.5 Gy, the development of cataracts was also slowed down. Only in isolated cases (2.6%) were clouding of the lens of the II stage 33 weeks after irradiation. By the 72nd week of observation, the frequency of lens opacities increased to 13.5%. The total frequency of lens opacities in animals of this group after 72 weeks exceeded the control level by approximately 3 times.

The tendency of a positive effect when using water with a low deuterium content can be traced quite clearly, delaying the formation of lens opacities and cataract maturation.

Table 1 Experimental scheme for studying the frequency of lens opacity in mice after gamma irradiation of ⁶⁰ Co in low doses Group of animals Experience Conditions Number of mice one Intact control twenty 2 Gamma irradiation 25 cGy 19 3 Gamma irradiation 50 cGy 19 four Gamma irradiation 100 cGy eighteen 5 Gamma irradiation 100 cGy + protium water 17

Claims (4)

1. A method of reducing the risk of radiation cataractogenesis during chronic exposure to low doses of ionizing radiation in mammals, including the introduction of pharmacological agents - radioprotectors into the body, characterized in that as a pharmacological agent - radioprotectors, water with a modified isotopic composition is used, namely with reduced concentrations of heavy stable hydrogen isotope - deuterium. 2. A method according to claim 1, characterized in that the concentration of the stable heavy isotope of hydrogen - deuterium is 1 to 140 million ^-1. 3. The method according to claim 1, characterized in that drinking water with lowered concentrations of the heavy stable isotope of hydrogen - deuterium is administered orally, parenterally or by instillation into the eye alone or as a solvent for physiologically active substances and pharmacological preparations. 4. The method according to claim 1, characterized in that drinking water with low concentrations of the heavy stable isotope of hydrogen - deuterium is introduced into the body before the chronic exposure to low doses of ionizing radiation, as well as during and after exposure to ionizing radiation.