To investigate the renal protective effects of spironolactone(SPR)and its possible mechanism indiabetic db/db mice.

Sixteen diabetic db/db mice were randomly divided into two groups by random number table:DM-SPR group(n=8)and DM group(n=8). Littermate db/m mice (NC group, n=10) were usedas normal control.Six-week-old DM-SPR mice were treated with SPR [20 mg/(kg·d)], while DM and NC group were both treated with nomal saline(NS) for 12 weeks.During the experiment, blood glucose, blood pressure and urinary albumin/creatine were measured. After the treatment for 12 weeks, all the mice were sacrificed and thekidneys were collected. Glomerular ultrastructure were observed undertransmission electron microscope. The mRNA expression of inflammation cytokines monocyte chemotactic protein-1(MCP-1), interleukin(IL)-1β,CD68 and fibrosis index collagen Ⅳ, fibronectin, transforming growth factor-β(TGF-β) were detected by realtime polymerase chain reaction(RT-PCR). One-way analysisofvarianceand q test were used for dataanalysis among groups.

At the 18-week, the levels of blood glucose and glycated hemoglobin A1c(HbA_1c) were both significantly higher in DM groupand DM-SPR groupthan those in NC group(glucose:q=-12.09, -14.49; HbA_1c:q=-8.86, -11.90, all P< 0.05),and there was no significant difference between DM group and DM-SPR group(q=-2.17, -2.09, all P> 0.05).There was no significant differences in systolic and diastolic pressure among the three groups(F=2.05, 2.75, bothP>0.05).There was significant differences in urinary albumin/creatine among the three groups(F= 9.12,P<0.05), it was higher in the DM group than that in the NC group(q=-5.79, P<0.05),and it was lower in the DM-SPR group than that in the DM group(q=4.03, P<0.05). In the DM group, reduction of fenestrated endothelium, thickening of glomerular basement memebrane(GBM)and diffuse effacement of podocyte foot process were commonly found underelectron microscope,while SPR treatment effectively improved theseinjuries.RT-PCR analysis showed that there were significant differences in mRNA expression of inflammatory cytokines CD68,MCP-1,IL-1β and fibrosis indexes TGF-β1, collagenⅣ, fibronectin among the three groups(F=4.38 to 9.85, all P<0.05); the expression of above mentioned indexes were all elevated in the DM groupwhen compared with those in the NC group(q=-6.18 to -3.53, all P<0.05), and the SPR treatment effectively decreased the expression of those indexes when compared with those in DM group(q=0.23 to 4.64, all P<0.05).

SPRplays protective rolesin the diabetic nephropathy in db/db mice, which maybe mediated by attenuatinginflammation and fibrosis.

Diabetic nephropathies; Spironolactone; db/db mice