10.22376/ijpbs.2019.10.1.p1-12 Volume 1 Issue 2 2010 (April - June) The anti-mutagenic activity of a PPAR-γ ligand pioglitazone (PIO-1 and 10 mg/kg, p.o daily for 4 weeks) was evaluated against the nicotinamide (NA-230 mg/kg, ip) and streptozotocin (STZ-65 mg/kg, ip) induced nuclear damage in diabetic Wistar rats. The NA-STZ diabetes significantly (P lessThan 0.001) increased the frequency of bone marrow micronuclei in erythrocytes and reduced the P/N ratio (polychromatic: normochromatic erythrocytes ratio) besides diminishing the serum antioxidant enzymes level. PIO at 10 mg/kg reduced (P lessThan 0.001) the incidences of micronuclei in erythrocytes as well increased (P lessThan 0.05) the P/N ratio in diabetic rats. The antioxidant study indicated that the higher dose of PIO (10 mg/kg) significantly (P lessThan 0.01) increased the SOD and catalase level, while the lower dose (1 mg/kg) enhanced (P lessThan 0.05) only the catalase level compared to the diabetic group. The results suggest that the inhibitory effect of PIO against the NA-STZ induced DNA damage could be due to its ability to enhance the antioxidant defense.  Syed Imam Rabbani,Kshama Devi,Salma Khanam Pioglitazone, nicotinamide, streptozotocin, bone marrow micronucleus, antioxidant. -