Myrtus communis subsp. communis improved cognitive functions in ovariectomized diabetic rats.

Abstract

The purpose of this study was to investigate the possible effects of Myrtus communis subsp. communis (MC) on cognitive impairment in ovariectomized diabetic rats. Female Sprague-Dawley rats were divided into 5 groups consisting of 15 rats each; Control (C), Diabetes (D), Ovariectomy and diabetes (OVX+D), Ovariectomy, diabetes and donepezil (OVX+D+Don), Ovariectomy, diabetes and Myrtus communis subsp. communis (OVX+D+MC). Blood glucose measurements were made at the beginning and end of the experiments. The animals underwent the novel object recognition test (NORT) and their performance was evaluated. In hippocampal tissues; amyloid beta (Aβ) and neprilysin levels, acetylcholinesterase (AChE), and choline acetyltransferase (ChAT) activities, polysialylated neural cell adhesion molecule (PSA-NCAM), α7 subunit of neuronal nicotinic acetylcholine receptor (α7-nAChR) and brain derived neurotrophic factor (BDNF) gene expressions were examined. Animals with ovariectomy and diabetes showed increased levels of blood glucose, AChE activity and Aβ levels, and decreased neprilysin levels, ChAT activity, α7-nAChR, PSA-NCAM and BDNF gene expressions in parallel with a decrease in NORT performance score. On the other hand, in the MC-treated OVX+D group, there was a significant decrease observed in blood glucose levels and AChE activities while there was improvement in NORT performances and an increase in hippocampal ChAT activity, neprilysin levels, α7-nAChR, PSA-NCAM and BDNF expressions. These results suggest that MC extract could improve cognitive and neuronal functions with its anticholinesterase and antihyperglycemic properties.