Figure 1.

Apoptosis in Madin-Darby canine kidney cell line; (a) Percent of apoptotic cells at 24 h in Madin-Darby canine kidney cells, after the treatment with 10 μM methotrexate alone and in combination of 10 μM methotrexate and 0.2 and 0.4 mM N-acetylcysteine; (b) Apoptosis in Madin-Darby canine kidney cells at 4 and 24 h after the treatment with 100 μM methotrexate alone and in combination of 100 μM methotrexate and 0.2 and 0.4 mM N-acetylcysteine; *P > 0.05, **P > 0.00. I: Control (PI and Annexin); II: 10 μM methotrexate; III: 10 μM methotrexate + 0.2 mM N-acetylcysteine; IV: 10 μM methotrexate + 0.4 mM N-acetylcysteine; V: 100 μM methotrexate; VI: 100 μM methotrexate + 0.2 mM N-acetylcysteine; VII: 100 μM methotrexate + 0.4 mM N-acetylcysteine