RU2469731C1 - Method of preventing radial pneumonitis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: method of preventing radial pneumonitis lies in inhalation of neomitilan in efficient quantity one hour before application of ionising radiation and a day after it.

EFFECT: reduction of pathophysiological action of ionising radiation on healthy tissues.

6 dwg, 2 tbl

Description

The invention relates to medicine, namely to medical radiology, and can be used for the prevention of radiation pneumonitis that occurs during radiotherapy of malignant tumors of the chest.

Radiation therapy is a method of treating tumor and a number of non-tumor diseases using ionizing radiation. The effect of radiation therapy is based on the increased sensitivity of cancer cells to ionizing radiation. In a number of diseases, radiation therapy complements chemotherapy and surgical treatment, improving the result.

However, treatment effectiveness is often limited by the presence of radiation reactions from surrounding tissues. The lung tissue is often exposed to ionizing radiation during radiation therapy of tumors of lung cancer, esophagus, breast, malignant neoplasms of the chest wall and mediastinum, lymphogranulomatosis. In the area of lung tissue that has been exposed to ionizing radiation, an inflammatory reaction always occurs - radiation pneumonitis, which occurs in the form of confluent segmental or lobar interstitial pneumonia. Later, late complications called pneumofibrosis develop in the place of acute inflammation, when the lung tissue damaged as a result of irradiation is replaced by connective tissue. Thus, the area of the respiratory surface of the lungs decreases, which leads to respiratory failure of varying severity, a dry cough and shortness of breath appear. The quality of life of patients is deteriorating, and often radiation pneumonitis becomes the immediate cause of human death.

The introduction of high energy sources into practice allows sparing surrounding tissues, however, the frequency of damage to the pulmonary parenchyma, especially in the area of tumor localization, remains high. The degree of risk depends on the size of the applied dose and the volume of irradiated lung tissue. For example, in breast cancer, the frequency of radiation injuries according to different authors is 10-100% depending on the dose of radiation, with radical programs of radiation (total total dose of 50-70 Gy) the likelihood of developing radiation injuries of the lungs is already 75-100% [Pasov V.V., Zubova N.D. et al. Late radiation injuries of the chest organs // Siberian Oncological Journal. 2009. P.58-61].

At the moment, in world practice there are no ways to prevent radiation pneumonitis, in the arsenal of doctors there are only ineffective methods of treatment.

With a mild course of radiation pneumonitis, it is sufficient to prescribe antitussive and antipyretic drugs and rest. Patients with more severe manifestations and impaired gas exchange are shown corticosteroids. Prednisolone is prescribed in a dose of 60-100 mg / day. After improving the condition and indicators of gas exchange (usually after 3-5 days), the dose of the drug is reduced to 20-40 mg / day and after 4 weeks its use is gradually discontinued. Corticosteroids are effective only in half of patients with radiation pneumonitis [Mihina Z.P. Radiation therapy for lung cancer. New in lung cancer therapy. Moscow. 2003].

The objective of the invention is the development of a method for the prevention of radiation pneumonitis using a drug with immunomodulatory, anti-inflammatory and wound healing effects, to protect against ionizing radiation during radiation therapy of cancer.

The problem is solved by the method of prevention of radiation pneumonitis, which consists in inhalation of a solution of neomitilan in an effective amount one hour before the use of ionizing radiation and a day after it.

An effective amount of an inhaled solution of neomitilan is 0.024 mg / mouse. With an average human weight of 80 kg, an effective amount of the drug is 0.096 g / kg.

Neomitilan has not previously been used for the prevention of radiation injuries.

Neomitilan - 1.4; 1,6-α-D-glucan, which contains glucose - not less than 98% and protein - not more than 1.5%, has a molecular weight of 2 MDa and is obtained from an extract formed by heating mussels in water for 1.0- 2.0 hours at 90-95 ° C, followed by purification by separating impurities by precipitation, dialysis on hollow fibers and chromatography on anion exchange resin [RU 2379044 C1, 01.20.2010].

The drug is nontoxic for mice when administered intraperitoneally in doses up to 2500 mg / kg, has immunomodulatory, wound healing, and anti-inflammatory effects.

It was previously shown that neomitilan reduces the level of lipid peroxidation (LPO) and the activity of nitroxide synthase [Chikalovets IV, Molchanova VI et al. Neomythilan - a new immunomodulator from mussel Crenomytilus grayanus // Pacific Medical Journal. 2009. No3. S.32-35]. An effective anti-inflammatory dose of neomitilan for inhalation in humans is 0.125 mg / kg. It was shown that all smoking volunteers with elevated levels of LPO and nitroxide synthase activity averaged 2-2.5 times compared with non-smokers after inhalation of a solution of neomitilan, a significant decrease in the level of these indicators in the exhaled breath condensate was observed. So, after inhalation of a neomitilan solution by smokers at a dose of 0.125 mg / kg after 1 hour and after 24 hours, the concentration of nitrite ion decreased by 35% and 75% and the MDA level decreased by 40% and 70%, respectively. It should be noted that neomitilan does not have a pyrogenic effect upon inhalation administration; fluctuations in the body temperature of volunteers did not exceed physiological values.

The results of the determination of allergic properties indicate that neomytilan does not affect the severity of delayed-type hyperergy in mice. In a conjunctival test, the studied bioglycan had practically no effect on the allergic reaction of the immediate type.

The technical result provided by the invention is to reduce the pathophysiological effect of ionizing radiation used for therapeutic purposes to treat tumors on healthy tissues. When used in mice, the thickness of the alveolar wall significantly decreases compared to that in animals irradiated but not treated with neomythylan.

The proposed method for the prevention of radiation pneumonitis is implemented as follows.

The experiments were performed on CBA mice (females weighing 18-20 g). The animals were kept in standard vivarium conditions of the TIBOKh FEB RAS in compliance with the rules and international recommendations of the European Convention for the Protection of Vertebrate Animals used for experimental and scientific purposes. In the experiment used 4 groups of animals, 8 animals in each study group:

1) animals treated with neomythilan;

2) irradiated animals;

3) animals irradiated and treated with neomythilan;

4) a control group.

Inhalation of Neomitilan Solution in Animals

The treatment of mice with neomitilan is carried out according to the following procedure: a group of mice is placed in a sealed reservoir connected to the tube of an Omron C28 ultrasonic inhaler. The dose for the mouse during inhalation of a solution of neomitilan (10 ml, 4 mg / ml) for 12 min in a chamber with a volume of 10 l is 0.024 mg / mouse intrapulmonary. Dose calculation was performed using data from inhalation of a fluorescein solution under similar conditions and determining its level in lung mouse extract.

The duration of the process of exposure to neomitilan is determined by the amount of inhaled drug and the exposure of animals in the chamber. During this time, they inhale an effective dose of neomitilan, which prevents the occurrence of side processes in the tissues of animals under ionizing radiation. 1 h after completion of the inhalation procedure, irradiation of the lungs of animals is carried out. The procedure for inhalation of animals with a solution of neomitilan is repeated one day after irradiation according to the previously described method.

Irradiation technique.

Irradiation is carried out on a device for close-focus gamma-therapy RUM-17 at a dose of 12 Gy, to the lung region, the remaining parts of the body are shielded with a 3 mm thick lead plate. The animals are placed in a wooden block 8 × 2.5 cm in size, belly down and covered with a lead plate 3 cm thick with a hole at the level of the chest size 2.5 × 2 cm.

Exactly one day later, the animals are re-treated with neomitilan according to the previously described procedure.

Material of study: lungs of experimental animals.

Mice are killed by the method of perivisceral dislocation. The material is obtained on the 28th day of the experiment and immediately after collection it is fixed in 10% neutral formalin. From the material by wiring according to the Merkulov scheme (table 1), paraffin blocks are obtained.

Table 1 Merkulov's scheme Commit: formalin 10% 24 h formolin alcohol 24 h Carnoy liquid 2-4 h alcohol 96-100% 2-24 h rinsing in running water 12-24 h Dehydration: alcohol 96% I 24 h alcohol 96% II 2 h alcohol 100% I 24 h alcohol 100% II 2 h Paraffin filling: alcohol-chloroform (1: 1) 6-12 h chloroform-paraffin (1: 1) at 37 ° C for 2-3 hours paraffin I at 56 ° C for 2 hours paraffin II at 56 ° C for 1 h

Using paraffin blocks using a Carl Zeiss HM 315 microtome, 3 μm thick sections were obtained and histological preparations stained with hematoxylin-eosin were prepared.

The study of histological preparations is carried out on a Carl Zeiss Axio Vision microscope with software v.8.0. The thickness of the alveolar wall in micrometers was taken into account. In each of the 32 preparations, 100 measurements of the thickness of the alveolar wall are performed using the electronic ruler, which is part of the Axio Vision v.8.0 software.

Figure 1 shows the relationship between the thickness of the alveolar wall in different groups of mice used in the experiment. It was shown that in the group of irradiated animals, the thickness of the alveolar wall is 8.54 μm greater than this parameter than in the control group, while in the group of animals irradiated and treated with neomythilan, this indicator exceeded the control group by 3.45 μm.

In Fig.2, this ratio is expressed as a percentage. It was shown that the protection against post-radiation pneumonia in the group of irradiated animals is 0%, while in the group where the irradiation was carried out using neomitilan, this indicator is 60%.

Figure 3 shows that during histological examination of the lung tissue on day 28 of the experiment in the control group, which was not subjected to special effects, pathological changes were not detected.

In Fig. 4 it is shown that during histological examination of the lung tissue on day 28 of the experiment, no pathological changes were detected in the group of animals inhaled with neomythylan.

It was shown that in the group of irradiated mice (Fig. 5), the average value of the thickness of the alveolar wall was 60% higher than that in the group of mice treated after irradiation with neomitilan (Fig. 6), and was 2.9 times higher compared to the control group.

In the group of animals irradiated and treated with neomythilan, the average value of the thickness of the alveolar wall is 1.8 times higher than in the control group. The results are presented in table 2.

table 2 Alveolar wall thickness in the control and experimental groups Group The control Neomytilan-treated animals Irradiated animals Animals irradiated and treated with neomythilan Value The average thickness of the alveolar wall (in microns) 4.42 4.70 12.96 7.87 Average error 0.14 0.11 0.41 0.25 n = 32 t = 10.73; p <0.01

Data are statistically significant (p <0.001).

A histological examination of the group of irradiated animals showed that the walls of the alveoli are sharply thickened, pronounced lymphoid infiltration, edema, and plethora of vessels are observed.

During a histological examination of a group of animals treated with neomythilan by the proposed method, the walls of the alveoli are slightly thickened due to slight edema, plethora of vessels, lymphoid infiltration weak and moderate.

Thus, it has been experimentally established that neomitilan has radioprotective properties. This opens up prospects for its use to reduce the pathophysiological effect of ionizing radiation on healthy tissues, used for therapeutic purposes to treat tumors.

Claims (1)

A method for the prevention of radiation pneumonitis, which consists in inhaling a solution of neomitilan in an effective amount one hour before the use of ionizing radiation and a day after it.

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