Topiroxostat improves glomerulosclerosis in type 2 diabetic Nagoya Shibata Yasuda mice with early diabetic kidney disease.

Reactive oxygen species production might be prevented by xanthine oxidoreductase (XOR) inhibitors, which can cause glomerulosclerosis. We aimed to investigate whether topiroxostat, an XOR inhibitor, prevents diabetic kidney disease development in mice. Six-week-old control Institute of Cancer Research (ICR) mice and type 2 diabetic Nagoya Shibata Yasuda (NSY) mice were divided into the ICR group (ICR mice which received a lard-containing high-fat diet [HFD] based on the AIN-93G diet), NSY control group (NSY mice which received the same aforementioned diet), and NSY + topiroxostat group (NSY mice which received the same aforementioned diet with addition of 0.0012% topiroxostat). After 20 weeks, plasma biomarkers, XOR activity and oxidative stress levels, which were assessed using malondialdehyde (MDA), were measured through enzyme-linked immunosorbent assay or enzymatic methods. Renal pathology was evaluated using periodic acid-Schiff staining. Redox gene and protein expression were determined using RT-qPCR and western blotting, respectively. Plasma XOR activity was lower in NSY mice treated with topiroxostat than those without. Plasma cystatin C and creatinine levels did not differ between the ICR and NSY control groups or between the NSY control and NSY + topiroxostat groups. The NSY + topiroxostat group showed a smaller mesangial area than the NSY control group. The mRNA expression of Sod3, Prdx1, Gpx2, and Gpx3 was higher in the NSY + topiroxostat group than in the NSY control group. Renal MDA levels were lower in the NSY + topiroxostat group than in the NSY control group. Topiroxostat can reduce glomerulosclerosis, and the reduction is associated with renal oxidative markers.