Effects Of ⁶⁰Coγ Radiation Exposure On Expressions Of CDKN1A, FABP4 And HSL In Human Lymphocytoblast

Ionizing radiation can induce a series of harmful biological incidents. The gene or protein which is radiosensitive, may serve as a biomelecule marker for remarking ionizing radiation, in order to estimate body radiation dose and to be used in irradiation protection. Cyclin-dependent kinase inhibitor 1A (CDKN1A) gene play an important role in regulating the cell cycle. Fatty acid-binding protein 4 (FABP4) and hormone-sensitive lipase (HSL) are close related to lipid disorders, inflammatory reaction, atherosclerosis and so on. Some reports and preliminary experiment in present study have indicated that the above-mentioned gene or protein belong to radiosensitive molecule. Relationship of these molecules` expressions and ionizing radiation dose and cell culture time, however, is still open so far, which is an aim of present study.Objective:This study was carried out to reveal the effects of <sup>60</sup>CoγRadiation exposure on expressions of gene CDKN1A, protein FABP4 and HSL in Human Lymphocytoblast with different radiation doses and various cell culture periods afterγ-ray radiation.Methods:1. Human lymphoblastoid cell lines (AHH-1) were radiated from the <sup>60</sup>Coγ-ray with different doses (0 Gy, 0.2 Gy, 1 Gy, 3 Gy, 5 Gy and 10 Gy) and were collected at various survival-sustained cell culture time (0 h, 4 h, 24 h, 48 h, 72 h and 96 h). The total RNA was extracted from each sample and the real-time PCR was conducted to detect the gene CDKN1A mRNA level changes in lymphocytoblasts with various radiation exposure doses and at different cell cultured time.2. Human lymphoblastoid cell lines (AHH-1) were irradiated by the <sup>60</sup>Coγ-ray with different lower doses (0 Gy, 0.1 Gy, 0.5 Gy and 1 Gy) and were collected at various survival-sustained cell culture time (0 h, 24 h, 48 h and 72 h). The total RNA and total protein was respectively extracted from each sample. The real-time PCR and Western blot was respectively operated to determine the gene FABP4 mRNA expression and the protein FABP4 and HSL level changes in lymphocytoblasts with various radiation exposure doses and at different cell cultured time.Results:1. Expressive levels of the CDKN1A mRNA in human lymphocytoblasts gradually went up with increasing radiation exposure doses, which showedγ-ray dose dependent from 0 Gy to 10 Gy (P<0.05), and reached the peak at cell-cultured time 24 h after radiation exposure while displayed a expressive downtrend during later time of cell culture.2. Expressive levels of the FABP4 mRNA in human lymphocytoblasts showed a fluctuant response with changes in radiation exposure doses, which level decreased in group of 0.1 Gy while increased in groups of 0.5 Gy and 1 Gy at cell-cultured time 24 h and 48 h after radiation exposure, compared with the unradiated group. Levels of the FABP4 mRNA displayed rise in different radiated group, especially, in groups of 0.1 Gy and 1 Gy at cell-cultured time 72 h after radiation exposure. Expressive multiple of the FABP4 mRNA in different radiated group at cell-cultured time 72 h after radiation exposure was more than that at other cell-cultured time points.3. Relative expressive levels of the FABP4 protein in human lymphocytoblasts did not show the significant changes with increasing radiation exposure doses at cell-cultured time 0 h, 24 h and 48 h after radiation exposure. Expressive multiple of the FABP4 protein in the radiated group of 1 Gy at cell-cultured time 72 h after radiation exposure was 2 folds as much as that in the unradiated group.4. Relative expressive levels of the HSL protein in human lymphocytoblasts did not show the significant changes with increasing radiation exposure doses at cell-cultured time 0 h and 24 h after radiation exposure. Expressive multiple of the HSL protein in the radiated group of 0.5 Gy at cell-cultured time 48 h after radiation exposure was 2 folds as much as that in the unradiated group but no significant differences obtained in groups with other doses. Expressive multiple of the HSL protein in the radiated group of 1 Gy at cell-cultured time 72 h after radiation exposure was 2 folds as less as that in the unradiated group but also no significant differences obtained in groups with other doses.5. Relative expressive levels of the FABP4 protein and HSL protein in human lymphocytoblasts with different radiation exposure doses and various cell-cultured time points after radiation exposure, campared with the unradiated group, showed an opposited change trend with increasing radiation exposure doses at cell-cultured time 24 h, 48 h and 72 h after radiation exposure.Conclusion:1. Ionizing radiation of the <sup>60</sup>Coγ-ray for the AHH-1 cells results in increases of the CDKN1A mRNA expression levels withγ-ray dose dependent from 0 Gy to 10 Gy within cell-cultured 24 h after radiation exposure, which may be used to evaluate the ionizing radiation dose.2. The transcription levels and protein levels of FABP4 expression in the AHH-1 cells significantly upregulate with different lower doses ofγ-ray radiation at cell-cultured time 72 h after radiation exposure.3. Relative expressive levels of the FABP4 protein and HSL protein in the AHH-1 cells with different lower radiation exposure doses and various cell-cultured time points, campared with the unradiated group, showed an opposited change trend with increasing radiation exposure doses at cell-cultured time 24 h, 48 h and 72 h after radiation exposure.4. Lower doses ofγ-ray radiation exposure may influence on the AHH-1 cells` lipid metabolism in the molecular level.