Aberrations and Apoptosis Induced in the Leukocytes of Hemoglobin H Disease Individuals after Irradiation

Alpha thalassemia is a set of hereditary anemia, which occurs frequently not only in the countries of the Mediterranean seacoast but also in the tropics and subtropics of the world including South East Asia and southern Iran. The -thalassemia can be generally categorized as: silent -thalassemia carrier, -thalassemia carrier, hemoglobin H disease, and -thalassemia major (hydrops fetalis). To study the effects of ionizing radiation on apoptosis and aberration induction in the leukocytes of hemoglobin H disease sufferers, compared to normal controls. Peripheral blood samples were obtained by venopuncture from ten healthy volunteers and ten Hb H patients.Blood samples were divided into two parts with one exposed to 3 Gy gamma rays generated from a 60Co source and the other without any irradiation. The blood samples were either immediately used for the comet assay or left in 37 ºC CO2 incubator for 48 hours in RPMI-1640 medium. Chromosome analyses were carried out exclusively on first division metaphases. For all samples, 70 metaphases were observed. Obtained data were statistically analyzed using SPSS (version 15) software. Results showed that the frequency of spontaneous aberration was similar in all the study groups. In normal individuals, in all the chromosomes except chromosome 1, a random distribution of break points proportional to their lengths based on their DNA content was observed. In hemoglobin H disease individuals, in all the chromosomes, a random distribution of break points proportional to their lengths based on their DNA content was observed. Results showed that the frequency of apoptosis in the leukocytes of freshly drawn blood of Hb H patients was significantly higher than that in the controls. Incubation of non irradiated samples in culture medium and CO2 incubator at 37 ºC for 48 hours greatly increased the frequency of apoptosis in all the samples. However, the frequency of apoptosis in Hb H patients was significantly higher than that in the controls. Irradiated samples kept for 48 hours in incubator prior to processing for comet assay, showed higher frequency of apoptosis, compared to non irradiated conterparts. We can conclude that among the -thalassemia patients those with HbH disease might be considered as radiosensitive in terms of apoptosis formation.