Cynomorium songaricum extract enhances novel object recognition, cell proliferation and neuroblast differentiation in the mice via improving hippocampal environment

BACKGROUND Cynomorium songaricum Rupr. (CS) has been used as a medicine to treat many diseases as well as to alleviate age-related issues, such as memory impairment, dementia, and stress. In this study, we assessed the effects of Cynomorium songaricum extract (CSE) on the novel object recognition, cell proliferation and neuroblast differentiation in the dentate gyrus of mice by using 5-bromodeoxyuridine (BrdU) and polysialylated neural cell adhesion molecule (PSA-NCAM). We also measured serum corticosterone levels to assess its correlation with neurogenesis and stress. METHODS Male C57BL/6 J mice were divided into 3 groups: vehicle-treated, 40 mg/kg CSE-treated, and 100 mg/kg CSE-treated. The vehicle and CSE were given to mice once a day for 3 weeks. BrdU was injected twice a day for 3 days to label newly generated cells. RESULTS Administration of CSE significantly increased the preferential exploration of new objects in these mice. In addition, administration of CSE decreased serum levels of corticosterone. BrdU-positive cells as well as brain-derived neurotrophic factor (BDNF) mRNA expression in the dentate gyrus were higher in the CSE-treated groups than in the vehicle-treated group. PSA-NCAM-positive neuroblasts and their well-developed tertiary dendrites were also significantly increased by the treatment of CSE. These effects were prominent at the higher dosage than at the lower dosage. CONCLUSION These results suggest that administration of CSE increases cell proliferation and neuroblast differentiation in the dentate gyrus of mice by reducing serum corticosterone levels and increasing BDNF levels in this area.