Effect of azidothymidine on the radiation-induced LDH release in HeLa cells

Treatment of HeLa cells with various concentrations of 0, 0.01, 0.1, 1, 10, and 100 μM AZT resulted in a concentration dependent elevation in the LDH release at 0, 0.5, 1, 2 and 4 h post-treatment. An elevation of 1.7 to 9.2 fold in LDH content was observed at 1 h post-treatment depending on the drug concentration. Similarly, treatment of HeLa cells with 0.1 μM AZT before irradiation caused an irradiation dose dependent increase in the LDH release in AZT + irradiation groups. This increase in LDH release was approximately two fold greater at 0 h post-irradiation in AZT + irradiation group, when compared with the PBS + irradiation group. This trend of elevation in LDH release continued up to 2 h, except 2 and 3 Gy, where it was 1.7 fold in the former group when compared with the latter. However, a peak level of LDH release was observed at 0 h post-irradiation.