The effect of pioglitazone on the liver of streptozotocin-induced diabetic albino Wistar rats.

BACKGROUND The present study was conducted to assess the effect of Pioglitazone, an oral antidiabetic drug with selective PPAR-gamma agonist effect; in a dose of 4 mg/kg B.W. once a day orally for eight weeks on the liver of streptozotocin-induced diabetic rats. MATERIAL AND METHODS Sixty male adult albino Wistar rats were equally randomly into six groups (n=10). Group I: normal control group was received no medication. Group II: distilled water control group, they are non diabetic group and received distilled water once a day orally by gastric tube for 8 weeks. Group III: citrate buffer control group, they are non diabetic received a single intraperitoneal injection of an equivalent amount of vehicle (citrate buffer, pH 4.5) 1 ml/kg at the time of induction. Group IV: Pioglitazone control group, they are non diabetic received pioglitazone HCl, single dose of 4 mg/kg b.w. once a day orally by gastric tube for eight weeks. Group V: diabetic control group, they are streptozotocin-induced diabetic rats that received no medication. Group VI: diabetic treated group, they are streptozotocin-induced diabetic rats treated by pioglitazone for eight weeks. RESULTS At the end of the experiment microscopic examination of the liver sections in the diabetic control group, showed mild to moderate portal inflammatory infiltrate, mostly lymphocytic as well as intralobular cell necrosis and apoptosis as well as bile stasis. These results were associated serologically with elevation of all liver parameters. Pioglitazone administration in the normal rats for eight weeks didn't show any significant difference neither serologically nor histopathologically compared with normal control group. Moreover, pioglitazone administration caused statistically significant reduction in the mean levels of liver tests, as well as fasting blood glucose of the STZ-induced diabetic rats. CONCLUSION There is no evidence that pioglitazone administration has a harmful effect on the liver. On the other hand, it has a potential beneficial effects on the liver during treatment of STZ-induced diabetic rats, suggesting that liver toxicity isn't a class effect of the thiazolidinediones but rather a unique effect of troglitazone.