Objectives: Ureteral obstruction results in an injury response that can progress to irreversible renal fibrosis and tubular atrophy by apoptosis. The molecular events leading to apoptosis from obstruction are not well understood. We investigated the effect of bioflavonoids and angiotensin II inhibition on apoptotic and inflammatory gene expression in a model of unilateral ureteral obstruction (UUO).
Methods: Complete UUO was produced in rats by ureteral ligation. The rats were treated with dimethyl sulfoxide (control), enalapril, losartan, curcumin, or quercetin. The animals were killed on day 7 and both obstructed and contralateral unobstructed kidneys were harvested. Expression of the inflammatory chemokine monocyte chemotactic protein-1, apoptosis effector genes Fas and Fas ligand, and oxidative stress gene HO-1 was evaluated by reverse transcriptase-polymerase chain reaction.
Results: Ureteral obstruction was associated with a 6.3-fold increase in monocyte chemotactic protein-1 expression compared with sham-operated rats (P = 0.01). Monocyte chemotactic protein-1 expression was severely attenuated in all other treatment groups (P <0.05). Similarly, Fas and Fas ligand expression were increased in control UUO kidneys compared with sham-operated ones (P <0.05). Fas gene expression was significantly inhibited by quercetin but not enalapril, losartan, or curcumin compared with the control. The induction of Fas ligand was attenuated in all treatment groups (P <0.05). HO-1 was expressed at low levels in both unobstructed and obstructed kidneys. Treatment with curcumin increased HO-1 expression fourfold (P <0.05).
Conclusions: The expression of apoptotic and chemokine genes is significantly upregulated in UUO. Bioflavonoids and angiotensin inhibitors are able to attenuate the expression of these genes and thus may be beneficial in renal protection.