The db/db diabetic renal injury model was used to examine the renoprotective effects of CBP, IGCO, TACO and IGRR. For mechanistic studies, diabetic symptoms, renal functions, and pathohistology of pancreas and kidney were evaluated. AGEs/RAGE/SphK1 pathway were determined.
CBP, IGCO, TACO and IGRR inhibited the decrease in serum insulin levels and the increases in urine volume, food consumption, water intake, TC, TG, glycated serum protein, fasting blood glucose levels, 24 h urine protein levels, and serum levels of urea nitrogen and creatinine. It also prevented ECM accumulation and improved the histology of pancreas and kidney, and alleviated the structural alterations in mesangial cells and podocytes in renal cortex. Moreover, CBP, IGCO, TACO and IGRR down-regulated the elevated staining, protein levels of RAGE, SphK1, TGF-β and NF-κB. Among the treatment groups, CBP produced the strongest effects.
These findings suggest that the inhibitory effect of CBP, IGCO, TACO and IGRR on the activation of AGEs/RAGE/SphK1 signaling pathway in db/db diabetic mice kidney is a novel mechanism by which CBP, IGCO, TACO and IGRR exerts renoprotective effects on DN. Among all the groups, CBP produced the strongest effect while IGCO, TACO and IGRR produced weaker effects.