Backcross db Gene into CD-1 Background Results in Novel Type 2 Diabetic Mouse Model with Progressive Kidney Fibrosis

Kidney fibrosis is the final common pathway of progressive kidney disease including diabetic kidney disease (DKD). With the rapid increase of type 2 diabetes, DKD in type 2 diabetic patients has become a serious public health threat around the world. To establish novel therapy to combat DKD, human disease relevant animal model is essential. However, a type 2 diabetic mouse model with presenting progressive kidney fibrosis is not established yet. We have previously reported that kidneys of streptozotocin-induced diabetic CD-1 mice exhibited severe fibrosis compared to other backgrounds of mice associated with the suppression of anti-fibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline, fibroblast growth factor receptor 1, and their downstream target anti-fibrotic microRNAs (miRs) such as miR 29 and miR let-7. As the type 2 diabetic mice model, leptin receptor deficient mice in BKS background (BKSdb/db) are often utilized; the kidney fibrosis in BKSdb/db phenotype is minimum. Here we backcrossed db gene into potential fibrotic CD-1 background and found that male CD-1db/db exhibited severe kidney fibrosis when compared to male BKSdb/db. We have already performed the backcrosses for 11 generations. Body weight of CD-1db/db was comparable but drank up to 3 times more water compared to BKSdb/db. Blood glucose levels in CD-1db/db appeared to be higher when compared to BKSdb/db. When evaluated the per body weight ratio, kidney and heart weighed no significant differences between CD-1db/db and BKSdb/db. CD-1db/db exhibited severe tubulo-interstitial fibrosis, glomerulosclerosis, and tubular epithelial cells damage. Heart in CD-1db/db displayed fibrotic change as well. In conclusion, here we provide novel fibrotic type 2 DKD mouse model. CD-1db/db could be excellent model to perform experimental therapy for DKD. Disclosure Y. Mizunuma: None. K. Nitta: None. S. Takagi: None. K. Kanasaki: Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Speaker's Bureau; Self; Eli Lilly and Company, Sanofi, Mitsubishi Tanabe Pharma Corporation. Research Support; Self; Boehringer Ingelheim GmbH. Speaker's Bureau; Self; Boehringer Ingelheim GmbH, Astellas, Astellas. Research Support; Self; Ono Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation. D. Koya: None.