The effects of safranal, a constitute of saffron, and metformin on spatial learning and memory impairments in type-1 diabetic rats: behavioral and hippocampal histopathological and biochemical evaluations

Safranal is one of saffron constituents and has antioxidant and neuroprotective properties. Metformin is used as an anti-diabetic drug. This study was planned to investigate the separate and combined treatment effects of safranal and metformin on diabetes-induced learning and memory impairments by behavioral and hippocampal histopathological and biochemical evaluations. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ), treatments with safranal (0.025, 0.1 and 0.4 mg/kg), metformin (50 and 200 mg/kg), and a combination of low doses of this chemicals were initiated after confirmation of diabetes and continued for 37 days. Blood glucose concentration was measured before and on days 15, 25 and 35 after injection of streptozotocin. Learning and memory tested using Morris Water Maze (MWM) on days 40-45 and on day 45 hippocampal specimens were collected for determination of malodialdehyde (MDA), tumor necrosis factor-alpha (TNF-alpha) and Caspase-3 levels and superoxide dismutase (SOD) activity. The hippocampus was also designed for light microscopy evaluation. Hyperglycemia, spatial learning and memory impairments, hippocampal neuron loss, increase of hippocampal MDA, TNF-a and caspase-3 levels and decrease of SOD activity were observed in diabetic rats. Safranal (0.1 and 0.4 mg/kg), metformin (200 mg/kg) and safranal (0.025 mg/kg) with metformin (50 mg/kg) improved the above-mentioned behavioral, histopathological and biochemical changes. Safranal and metformin and their combination improved learning and memory impairments in STZ-induced diabetic rats. Antioxidant, anti-inflammatory and antiapoptotic mechanisms might be involved. It is recommended that safranal be considered for diabetes management.