Table 1.

Study design.

Group	n	Received
Control	10	Animals were given normal saline as the vehicle for cadmium chloride by gavage (10 mL/kg/day). Likewise, carboxymethyl cellulose (CMC; 0.5%) was given as linagliptin vehicle by gavage to animals. Each day, the 2 doses were separated by 2 h to avoid potential interaction. The treatments were received for 8 weeks.
Control + LIN	10	Animals were given saline (10 mL/kg/day). In addition, linagliptin (5 mg/kg/day; 10 mL/kg/day) was given by gavage. Each day, the 2 doses were separated by 2 h to avoid potential interaction. The treatments were received for 8 weeks.
Cd	10	Animals were given cadmium chloride solution by gavage (5 mg/kg/day; 10 mL/kg/day). In addition, animals received an oral gavage of CMC (10 mL/kg/day). Each day, the 2 doses were separated by 2 h to avoid potential interaction. The treatments were received for 8 weeks. The chosen regimen is in accordance with published studies [29,43,44].
Cd + LIN	10	Animals were given cadmium chloride solution by gavage (5 mg/kg/day; 10 mL/kg/day). In addition, linagliptin (5 mg/kg/day; 10 mL/kg/day) was given by gavage. Each day, the 2 doses were separated by 2 h to avoid potential interaction. The treatments were received for 8 weeks. The selected linagliptin dose was based on literature that demonstrated such dose as effective for amelioration of streptozotocin-induced diabetic dementia [13] and high-fat-evoked cognitive deficit in PS19 transgenic mice [19].