Cytokine gene expression in Adriamycin nephropathy: effects of antioxidant nuclear factor kappaB inhibitors in established disease.

BACKGROUND/AIM: Inhibition of nuclear factor kappaB with the antioxidant pyrrolidine dithiocarbamate (PDTC) reduced tubulointerstitial injury in Adriamycin nephropathy (AN), whereas N-acetylcysteine (NAC) was ineffective. Here we hypothesize that PDTC reduces the renal cortical expression of nuclear factor kappaB dependent cytokines in AN.

METHODS

Male Wistar rats received a single intravenous injection of doxorubicin hydrochloride (7.5 mg/kg). NAC (150 mg/kg twice daily i.p.), PDTC (50 mg/kg twice daily i.p.), or vehicle were commenced on day 14 and continued until day 30.

RESULTS

On day 30, mRNAs of selected cytokines were increased in AN (TNF-alpha 3.4-fold, MCP-1 5.1-fold, IL-10 2.7-fold, TGF-beta1 3.5-fold, all p < 0.05) as determined by RT-PCR. PDTC reduced IL-10 and TGF-beta1 mRNAs (p < 0.05), whereas the upregulation of MCP-1 and TNF-alpha mRNAs was not affected. In contrast, NAC increased TNF-alpha and IL-10 mRNAs (p < 0.05). Nuclear protein levels of activator protein-1 were increased in AN (4.4-fold, p < 0.01) and not significantly altered by PDTC (3.0-fold, p = 0.13) or NAC (5. 2-fold, p = 0.18).

CONCLUSIONS

The protective effects of PDTC in AN are not associated with a local reduction in TNF-alpha and MCP-1 gene expression. The latter may be due to continued transactivation by activator protein-1. These data also suggest that IL-10 and TGF-beta1 mRNA expressions are PDTC dependent and have a role in mediating tubulointerstitial injury.