Activation of poly(ADP-ribose) polymerase inhibited the apoptosis of rat thymocytes induced by short-wavelength ultraviolet irradiation

摘要

The effect of (i) aphidicolin, a specific inhibitor of #delta#-and #epsilon#-polymerase, and nucleotide excision repair; (ii) 3-aminobenzamide, an inhibitor of poly(ADP-ribose) polymerase and base excision repair; and (iii) actinomycin D and cycloheximide, inhibitors of protein and RNA synthesis, respectively, on the induction of suppression of apoptosis of rat thymocytes by different doses of short-wavelength ultraviolet radiation was studied by flow cytometry. 3-Aminobenzamide suppressed the inhibition of apoptosis induced by the doses of short-wavelength ultraviolet radiation higher than 20 J/m~2, increasing the cell death to a maximum. Thus, the inhibition of apoptosis by high short-wavelength ultraviolet radiation doses depends on the status of poly(ADP-ribose) polymerase and is prevented by 3-aminobenzamide. As opposed to 3-aminobenzamide, aphidicolin did not affect the cell heath at short-wavelength radiation doses higher than 10 J/m~2 but induced the apoptosis of unirradiated cells and cells irradited with short-wavelength ultraviolet radiation doses lower than 10 J/m~2. The inhibitors of protein and RNA synthesis cycloheximide and actinomycin D prevented the induction of apoptosis caused by low and medium doses but did not not abolish the apoptosis-inhibiting activity of high doses of short-wavelength ultraviolet radiation.