Цитогенетический анализ клеточной линии мультипотентных мезенхимальных стромальных клеток человека при длительном культивировании после воздействия рентгеновского излучения в малых и средних дозах

Abstract

Purpose: To evaluate the frequency and spectrum of chromosome aberrations under X-Ray exposure at doses of 80, 250, and 1000 mGy in a human multipotent mesenchymal stromal cell (MMSC) cell line during long-term cultivation. Material and methods: MMSCs were isolated from human gingival mucosa by an enzymatic method and cultured in a serum-free medium. The presence of surface antigens was determined using the method of flow cytometry. The ability of the cell line to differentiate in the osteogenic, adipogenic, and chondrogenic directions was studied using induction media. Authentication was performed by genotyping of polymorphic STR loci, cytogenetic analysis was performed by multicolor fluorescent in situ hybridization (mFISH). Irradiation was carried out on an X-ray biological unit RUB RUST-M1 (Russia) at a dose rate of 40 mGy/min, a voltage of 100 kV, and a current of 0.8 mA. Results: At the first passage after irradiation, a statistically significant increase in the frequency of non-clonal CA compared with the control was recorded at a dose of 80, but not 250 and 1000 mGy. At the late stages of cultivation, the average frequency of breaks per chromosome in the group of non-irradiated cells did not differ from the values obtained after irradiation at doses of 80, 250, and 1000 mGy (p > 0.05). However, in MMSCs irradiated at a dose of 80 mGy, damage occurred more often in pairs of chromosomes 6 and 10, and at a dose of 1000 mGy, in a pair of chromosomes 9. A single irradiation of MMSCs in vitro did not affect the growth and progression of MMSCs characteristic of the studied primary cell line, of clonal cells with chromosome translocations and monosomy X, but led to an increase in the representation of a clone with tetrasomy 8. The total number of random clones with chromosome translocations that arose de novo increased after irradiation at a dose of 1000 mGy. Conclusion: Minor fluctuations in the proportion of cells with non-clonal CA, depending on the dose received in the early stages after irradiation (passage 1–4), disappeared at the later stages of cultivation (passage 8–14). There were no differences in mean frequencies between irradiated and non-irradiated MMSCs, but after irradiation, damage to some chromosomes could occur more frequently than others. A single X-ray irradiation of MMSCs can promote the growth and progression of primary pathological cytogenetic clones, regardless of the dose received, as well as an increase in the total number of de novo cell clones with chromosomal translocations that have arisen. A single X-ray irradiation of MMSCs can promote the growth and progression of primary pathological cytogenetic clones, regardless of the dose received, as well as an increase in the total number of de novo cell clones with chromosomal translocations that have arisen.