State of Immunological Reactivity of Rat’s Body after Exposure to Different Doses of γ-Radiation in a Long Period and their Offense of the 1st Generation

Abstract

Abstract

BACKGROUND: Recently, the problem of changes in immunological reactivity has become important with the growth of immunodeficiency states of a different nature. [4]. High radiosensitivity of the immune system, its stability in time and the irreversibility of some post-radiation changes can contribute to the development of long-term effects of radiation [2,3,6]. One of the tasks of modern medicine and biology is to study the effect of chronic or fractionated ionizing effects on the body's immune system both in the early and late periods of irradiation and their 1st generation descendants [1,2,3,11,12].  Therefore, it is necessary to study the long-term effects of sublethal and fractionated effects of g-radiation on the immunological reactivity of the organism, nonspecific phagocytic resistance and their 1st generation descendants.

AIM: The aim of this study was to study the long-term effects of sublethal and fractionated effects of g-radiation on the immunological reactivity of the organism, nonspecific phagocytic resistance and their 1st generation descendants..

METHODS: 7 series of experiments were performed on 105 white outbred sexually mature rats. 1-series intact (n=15), 2nd series - (n = 15) irradiated with a sublethal dose of 6 Gr. (1 month), 3rd series - irradiated with a sublethal dose (3 months, n = 20), 4 - descendants 1 - generations after sublethal dose, 5 series - irradiated with a fractionated dose (1 month), 6 series - irradiated with a fractionated dose (3 months), 7 - descendants of the 1st generation after fractionated -irradiation. Each series used 15 animals.     Irradiation of animals 2 - 3 - 4 series was carried out on the Russian radiotherapy device "Agat-RM" -rays 60Co, the dose of sublethal irradiation is 6 Gr. Irradiation of animals of 5-6-7 series was carried out on the Russian radiotherapy device "Agat-RM" with 60Co-rays with topometric and dosimetric preparation of experimental animals, which facilitates the administration of a fractionated dose of 2 Gr. to animals three times within 3 weeks.

RESULTS: In the long-term period after fractionated g-irradiation in the T-system of immunity, the following changes occur: against the background of an increase in the total number of lymphocytes, there is a decrease in the pool of CD3 +, CD4 + lymphocytes, immunoregulatory index, normalization of the lymphokine-producing ability of lymphocytes and a decrease in the pool of CD8 + lymphocytes. In the long-term period after fractionated g-irradiation in the humoral link of immunity, an increase in the absolute amount of CD19 + by 3.5 times was noted, which significantly exceeded the indicators of both control and intact animals. The percentage of this pool of cells exceeded the data of intact ones by 1.7 times. In the studied time period, the antibody-producing ability in the spleen increased from 22 ± 1.3 to 45 ± 2.6, without reaching, however, the level of intact animals. At the same time, there was a significant decrease in the suppression index to 13% (P<0.001) and the CIC concentration by 14 times (P<0.001) in the blood serum. The indicators of F/n and NST-test were high by 1.43 and 2.46 times, respectively. So, in the long-term period after exposure to a fractionated dose of g-radiation, the nonspecific phagocytic resistance of the organism is increased.

CONCLUSIONS: The tension in the humoral link of immunity is manifested by a decrease in the quantitative and qualitative indicators and an increase in the functional and metabolic activity of neutrophils.