The present study aims at using the biological techniques in a genotoxicity assessment of low doses of radiation in samples of workers in Al-Tuwaitha site due to decommissioning to radioactive contamination as a result of work. This study included 50 male blood samples, aged 35 - 63 years as well as 35 blood samples from non-smokers and non-alcoholic as control group which included 25 male and 10 female aged 25 -57 years. The endpoints used were sister chromatid exchange (SCE) and hypoxanthine guanine phosphoribosyl transferase (HPRT) mutation assay. The sister chromatid exchange in the human lymphocyte for radiation worker was significantly (P<0.05) higher than in the control group. While the results of mutation for HPRT were non-significant when compared with the control group. In conclusion, the results indicated the possibility of using the changes in sister chromatid exchange as useful biomarkers for the detection of human exposure to ionizing radiation. In conclusion, the increase frequencies of sister chromatid exchange in radiation workers indicate the cumulative effect of low-level chronic exposure to ionizing radiation.
The present study aims to use the biological techniques in a genotoxicity assessment of DNA damage in peripheral lymphocytes of radiation workers at Al-Tuwaitha site due to decommissioning to radioactive contamination as a result of work during January 2010 to December 2011. The subjects were divided into two groups: (i) 85 workers from radiation workers at Al-Tuwaitha site; (ii) 50 controls were matched non-smoking and no alcohol drink. Fresh blood samples were collected from the workers and controls. Four genetic parameter were studied using the micronucleus (MN) test, nuclear division index (NDI) test, the comet assay and hypoxanthine guanine phosphoribosyl transferase (HPRT) mutation assay. The results of the MN test showed that the average of MN per cell (Mean ± SE) in workers were 0.025 ± 0.0016 MN/ cells, which were significantly higher than those 0.010 ± 0.0006 MN/ cells in controls P< 0.01. While, the results of NDI test the average of NDI (Mean ± SE) in workers were 1.154 ± 0.0089 when compared with the control 1.322 ± 0.0117, which were significant increase p<0.01. It was found in the comet assay that the mean tail length (Mean ± SE) of radiation workers and controls were 17.69 ± 0.23 µm and 14.05 ± 0.13 µm, respectively. There was a significant difference between radiation workers and controls for mean tail length P < 0.01, but the difference between the mean tail moment (Mean ± SE) 14.22 ±0.21 of workers and mean tail moment 12.96± 0.15 of controls was not significant P> 0.01. Mean while, the results of the average of mutation frequency for HPRT were no significant differences rate for radiation workers compared with the control group P> 0.01. In conclusion, the results of our experiment suggest that the accumulation of genetic damage is detectable in peripheral lymphocytes of radiation workers at Al-Tuwaitha site. Also, the current results of frequency MN and NDI within of normal values according of the technical report of International Atomic Energy Agency (IAEA) No. 405, 2001.
The present study aims to determination of GADD45 and CDKN1A expression genes as a biomarkers for ionizing radiation in white mice Mus musculus Balb/C by using the real-time quantitative PCR assay. Seventy- two white mice (36 males and 36 females) were divided into two groups; their whole body was exposed to 5 cGy and 100 cGy of X-ray radiation at a dose rate of 200 cGy/min, in addition to the control group. Total RNA was isolated using Trizol method from liver samples of mice after 6, 48 hours and 10 days of exposure to radiation as well as of the control group. Complementary DNA was used in amplification of genes used in the present study, two types of primers pairs were selected for the genes amplification Growth arrest and DNA-damage inducible A (GADD45A) and Cyclin-dependent kinase inhibitor 1A (CDKN1A), which have a relation with ionizing radiation in addition to the primers for internal control (β-actin) gene. The size amplified product were 95 bp and 162 bp nitrogen-base pair for GADD45A and CDKN1A genes, respectively. The existence of significant elevation p <0.05 in the amount of gene expression of the GADD45A gene in samples of mice liver exposed to doses 5 cGy and 100 cGy after 6 hours of exposure to radiation. It was found that this gene having up-regulation level after 6 hours in the liver of mice exposed to these doses in comparison with the control group. The presence of a significant reduction (p <0.05) in the amount of gene expression of the CDKN1A gene in samples of mice liver exposed to doses 5 cGy and 100 cGy after 6 hours of exposure to radiation and this reduction continued after 24 hours and 10 days. Moreover, it was found that this gene had a down-regulation level after 6 hours in the liver of mice exposed to these doses in comparison with the control group. The organizational level in the high dose of 100 cGy is higher than that at the low dose 5 cGy. In conclusion, the results indicated that there is a possibility of using the changes in the level of GADD45A and CDKN1A genes expression as useful biomarkers in assessment of DNA damage for low and high radiation exposure.
Comet assay (Single cell electrophoresis assay ,SCGE) is a very sensitive method to determine DNA damage caused by exposure to mutagenic , carcinogenic and environmental agents that affect women infertility. This study was aimed to assess possible genomic instability in women with recurrent spontaneous abortion (RSA). Fifteen blood samples were collected from women complaining with RSA and 5 normal fertile females, who had at least one or more child. The results showed that patients female with RSA had a significant higher DNA damage than in the control group.
A Study performed on 30 Iraqi radiation Labors had been exposed tо a low dose tо ionizing radiation at Al-Amal Cancer Hospital in Baghdad the use of three genetic endpoints. Covered 12 females and 18 males between the aged tо (22-57) years. In addition to 20 Healthy individuals from the population, dwelling Baghdad, covered, 7 females and 13 males, aged (19 - 55) years which are non-smokers, non- alcoholic. The cytogenetic analysis, including, HPRT gene mutation¸ comet assay and SCE have been carried out on peripheral blood lymphocytes of labors and control groups. The HPRT gene mutation assay showed a significant increase (p<0.05) in the radiation labors. There were found a significant increase (p<0.05) in comet tail length and tail moment values in thе human lymphocyte in these radiation Labors compared with thе control group. Also the SCE in human lymphocyte for radiation Laborers was significantly (p<0.05) higher than in a control group. Results obtained confirmed the cytogenetic analysis; including, HPRT gene mutation¸ comet assay and SCE are useful as biodosimetric markers for the detection of human exposure to low doses of ionizing radiation. It reflects the simultaneous exposure and actual levels of DNA damage present in radiological laborers' peripheral blood leukocytes by detecting temporary DNA damage and / or repair activity.
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