Background: Urtica dioica L. (stinging nettle) has been accepted for decreasing blood glucose levels; however, the exact mechanism of its anti-hyperglycemic effect remains to be understood. Objectives: We aimed to examine the effects of ethanolic extract of stinging nettle leaves on blood glucose levels and gene expression of Glucose Transporter 2 (Glut2) in liver of alloxan-induced diabetic mice. Materials and Methods: Twenty-four male Naval Medical Research Institute (NMRI) mice were randomly divided to three groups. The control group received saline (10 mL/kg, intraperitoneally) for eight days, the diabetic group received three days of injections of alloxan (200 mg/kg, intraperitoneally) followed by five days of injections of ethanol (20%), and the diabetic + nettle extract group received alloxan for three days followed by five days of injections of the nettle extract (150 mg/kg). Mice were weighed before and after treatments (on days one and nine). On day nine, mice were sacrificed, blood samples were collected for measuring glucose levels and liver was dissected to examine changes in the Glut2 gene expression with the semi-quantitative reverse-transcription-polymerase chain reaction (RT-PCR) method. Results: The results showed that the nettle extract significantly decreased high levels of blood glucose (P < 0.001). The nettle extract also had a preventive effect on decrease in body weight. In addition, the results showed that the Glut2 gene expression was increased in liver of diabetic mice (P < 0.05) and was significantly prevented by the nettle extract in diabetic + nettle extract group (P < 0.05). Conclusions: It can be concluded that the nettle extract can reduce blood glucose levels in diabetic mice, at least partly, by influencing the Glut2 gene expression in mice livers.
