[Optimization of streptozotocin dosing for establishing tumor-bearing diabetic mouse models]

To determine the optimal dosing of streptozotocin (STZ) for establishing lymphoma-bearing diabetic mouse models.

A total of 200 healthy male Balb/c mice were randomized into 4 groups (n=50) for intraperitoneal injection of a single dose of vehicle solution (control) or 75, 150, or 200 mg/kg STZ. The changes of body weight and blood glucose were observed regularly, and the success rate of modeling, mortality rate, and survival of the mice were recorded after the injections. The mice with successfully induced diabetes received subcutaneous or tail vein injection of A20 lymphoma cells, and the rate of tumorigenesis, mortality rate, and survival time were observed at 1 month and 3 months after tumor cell injection.

Compared with the control group, the mice receiving STZ injection at 150 and 200 mg/kg showed significantly decreased body weight and increased blood glucose (P<0.05), while STZ at 75 mg/kg did not produced such obvious changes. STZ injection at 200 mg/kg resulted in a significantly higher mortality rate and shorter survival time than STZ at 150 mg/kg (P<0.05). In the control group and 150 and 200 mg/kg STZ groups, the rate of tumorigenesis or mortality rate showed no significant differences after subcutaneous injection of A20 lymphoma cells (P>0.05), but differed significantly at 3 months after tail vein injection of the tumor cells (P<0.05).

Intraperitoneal injection of STZ at 150 mg/kg is associated with a low mortality rate, a high successful modeling rate of diabetes and a long survival time in mice, and is therefore optimal for establishing diabetic mouse models bearing transplanted tumors.