[Effect of curcumin on the expression of p-STAT3 and IκB in db/db mice]

To determine the effect of curcumin on diabetic nephropathy in db/db mice and its possible mechanism.

Ten female db/db mice were randomly divided into 2 groups: one was treated with curcumin at 200 mg/(kg.d) and the other was a placebo group. Five age-matched db/m mice were grouped as the controls. In the curcumin group, curcumin was administered to db/db mice for 18 weeks. At the end of the experiment, the blood glucose and albumin were measured, and the kidney tissue sections were stained with PAS to observe the pathological changes. The expression of collagen IV and FN in the kidney was detected by immunohitochemistry staining. Western blot was used to detect the phosphorylation of signal transducer and activator of transcription 3 (STAT3) and IκB in the kidney.

Compared with db/m mice, the weight and blood glucose of db/db mice were markedly increased, accompanied with heavy proteinuria, glomerulus hypertrophy, mesangial area expansion, thickening of basement membrane and ECM deposition. The phosphorylation of STAT3 was upregulated and the degradation of IκB was increased. Compared with the db/db mice, curcumin significantly decreased the urinary albumin, inhibited the phosphorylation of STAT3 and the degradation of IκB, and reduced the expression of collagen IV and FN in the kidney.

Curcumin can obviously decrease albuminuria and attenuate glomerular sclerosis in diabetic db/db mice by inhibiting phosphorylation of STAT3 and degradation of IκB.