Effect of the sodium–glucose cotransporter 2 inhibitor luseogliflozin on pancreatic beta cell mass in db/db mice of different ages

To examine the effects of luseogliflozin, a sodium–glucose cotransporter 2 inhibitor, on pancreatic beta cell mass in db/db mice of different ages. db/db mice aged 6, 10, 14 and 24 weeks old were fed either standard chow (control group) or standard chow containing 0.01% luseogliflozin (luseo group). After 4 weeks, immunohistochemistry and gene expression tests were conducted. In 6-week-old db/db mice, immunohistochemistry revealed a significant increase in beta cell mass in the luseo group compared with the control group after 4 weeks of treatment. Gene expression profiling of isolated islets showed upregulation Mafa, Pdx1, Ki67 and Ccnd2 in the luseo group. Beta cell mass decreased with age in db/db mice in the control group. Beta cell mass in the luseo group significantly increased compared with the control group regardless of age, although beta cell mass in the 28-week-old luseo group (4 weeks of treatment in 24-week-old db/db mice) was significantly lower than in the 10-week-old luseo group (4 weeks of treatment in 6-week-old db/db mice). Luseogliflozin preserved beta cell mass in db/db mice. The protective effect was more evident in the earlier phase of diabetes.