metformin ameliorates learning and memory deficits in streptozotocin-induced diabetic rats

Background and objective: diabetes mellitus (dm) in long-term is associated with learning and memory decline. metformin is an anti-diabetic drug with antioxidant and memory-improving effects. thus, this research study was conducted to assess the effect of metformin on learning and memory in diabetic rats. materials and methods: in the present study, male wistar rats (n=32) were randomly assigned to 4 groups: control, control treated with metformin (200 mg/kg), diabetic, and diabetic treated with metformin (200 mg/kg). diabetes was induced by streptozotocin (stz) at a dose of 60 mg/kg. metformin was administered i.p. at a dose of 200 mg/kg one week after stz injection for 7 weeks. blood sample was taken from retro-orbital plexus before stz injection and 4 and 8 weeks after stz injection to measure blood glucose level. passive avoidance and y maze tests were performed to evaluate learning and memory dysfunctions. results: after 8 weeks, diabetic rats showed a significant cognitive decline in passive avoidance and y maze tests that was significantly improved after metformin treatment. in addition, metformin exerted a significant hypoglycemic effect in this model of dm. conclusion: this study clearly showed that treatment with metformin for 7 weeks could ameliorate cognitive decline in diabetic animals and part of its beneficial effect is due to its hypoglycemic effect.