DNA damage and over expression of P53 and Hsp70 in mononuclear leukocytes exposed to X rays

The objective of the work was to evaluate the damage to the DNA as well as the expression of p53 and Hsp70 in human mononuclear leukocytes exposed to X-rays. The biological model used was peripheral blood human mononuclear leukocytes (PBHML) and isolated by clinical exclusion of healthy patients. The cell viability and the initial cell quantity were evaluated for each exposure dose, 14 aliquots were taken for the exposure protocol. The lymphocytes were exposed to a source of X-rays from a Corix equipment, of 70 K Vp-8 m A and exposure time of 0.15s for different absorbed doses of: 2.3, 4.6, 9.1 and 13.7 mGy. The response of DNA damage was quantified by agarose gel electrophoresis, p53 expression and Hsp-70 was performed by SDS Western Blot Page, specific monoclonal antibodies were used for the identification of p53 and Hsp70 and revealed Dab and H₂O₂, or with Ecl. The results for initial cell viability were 100% and the cellular amount was 88.333 ± 4784 LMHSP. The feasibility behavior in the irradiation protocol was observed a significant difference of decrease in comparison with the negative control for the first three exposures and in the behavior of the cell quantity a significant decrease was observed for the last two exposures. For damage to the DNA, damage was observed proportional to the dose of radiation received, although significant only for the doses of 9.1, 13.7 mGy and positive control (sample subjected to heat stress, 44 degrees Celsius / 1 hr). In addition, a basal expression of p53 and Hsp70 was observed in the negative control, and on overexpression in the doses of 9.1 and 13.7 mGy for p53 and Hsp70, as well as for the positive control (44 degrees Celsius / 1 hr). Conclusion: the findings allowed estimating a molecular damage response and that p53 and Hsp70 proteins can be used as bio markers for exposure to users of X-ray equipment with these characteristics and assumes a significant importance in radiological protection. (Author)