Effect of pioglitazone on renal osteopontin expression in diabetic rats / 中国药学杂志

ABSTRACT

OBJECTIVE: To investigate the effect of pioglitazone on renal osteopontin expression in diabetic rats. METHODS: Sprague Dawlry rats were randomly divided into the normal control group and the model group. Diabetes was induced by streptozotocin (STZ) in the model group rats. After diabetes was confirmed, diabetic rats were assigned randomly into three subgroups; the diabetic rats without treatment, 3 and 15 mg · kg-1 · d-1 pioglitazone treated diabetic rats. At the end of the 8th week, 24h urine samples were collected to examine microalbuminuria (mAlb). At the same time, blood glucose levels and serum creatinine (Scr) were measured. Stained kidney sections were observed under light microscope. The expressions of OPN protein and OPN mRNA were detected by immunohisto-chemistry and reverse transcription-polymerase chain reaction (RT-PCR), respectively. RESULTS: Treatment with 3 and 15 mg · kg-1 · d-1 pioglitazone could decrease Scr, mAlb and RKW in diabetic rats. Compared with diabetic rats, blood glucose level was lower in diabetic rats treated with 15 mg · kg-1 · d-1 pioglitazone however, no significant change was observed at the 3 mg-1 kg · d-1 dose. Compared with normal control rats, the OPN protein and mRNA expressions of the whole nephritic kidney in diabetic rats were upregulated (P<0.05). After treatment with 3 and 15 mg · kg-1 · d-1 pioglitazone, the expressions of OPN protein and mRNA reduced compared with diabetic rats (P<0.05). CONCLUSION: The OPN expression in renal tissues is increased in diabetic rats, suggesting that OPN has emerged as a potential key pathophysiologic contributor in diabetic nephropathy (DN). Pioglitazone can reduce microalbuminuria in diabetic rats. The renal protective effect of pioglitazone in DN may involve the suppression of increased OPN.