Shahed University

Diosgenin Attenuates Cognitive Impairment in Streptozotocin-Induced Diabetic Rats: Underlying Mechanisms

Mehrdad Roghani | Ashkan Sanaeierad | Zahra Kiasalari Reineh | Siamak Afshinmajd | Gholamali Naderi | Tayebe Rahmani | Tourandokht Balouchnejad | Narges Mahmoudi

Date :  2020/06/28
Publish in :    Neuropsychobiology

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Keywords :diabetes mellitus,streptozotocin, Diosgenin,learning and memory,cognition

Abstract :
Prolonged diabetes mellitus causes impairments of cognition and attentional dysfunctions. Diosgenin belongs to a group of steroidal saponins with reported anti-diabetic and numerous protective properties. This research aimed to assess the effect of diosgenin on beneficially ameliorating learning and memory decline in a rat model of type 1 diabetes caused by streptozotocin (STZ) and to explore its modes of action including involvement in oxidative stress and inflammation.Methods:Rats were assigned to one of four experimental groups, comprising control, control under treatment with diosgenin, diabetic, and diabetic under treatment with diosgenin. Diosgenin was given daily p.o. (40 mg/kg) for 5 weeks. Results: The administration of diosgenin to the diabetic group reduced the deficits of functional performance in behavioral tests, consisting of Y-maze, passive avoidance, radial arm maze, and novel object discrimination tasks (recognitive). Furthermore, diosgenin treatment attenuated hippocampal acetylcholinesterase activity and malon­dialdehyde, along with improvement of antioxidants such as superoxide dismutase and glutathione. Meanwhile, the hippocampal levels of inflammatory indicators, namely interleukin 6, nuclear factor-κB, toll-like receptor 4, tumor necrosis factor α, and astrocyte-specific biomarker glial fibrillary acidic protein, were lower and, on the other hand, tissue levels of nuclear factor (erythroid-derived 2)-related factor 2 were elevated upon diosgenin administration. Besides, the mushroom-like spines of the pyramidal neurons of the hippocampal CA1 area decreased in the diabetic group, and this was alleviated following diosgenin medication. Conclusions: Taken together, diosgenin is capable of ameliorating cognitive deficits in STZ-diabetic animals, partly due to its amelioration of oxidative stress, inflammation, astrogliosis, and possibly improvement of cholinergic function in addition to its neuroprotective potential.