Objectives: Chronic stress exposure can disrupt the balance of organisms, result in learning and memory impairments and induce oxidative stress. However, there is a lack of safe and effective long-term therapeutic agents for stress-related injuries. Fresh ginseng (FG), an unprocessed raw root of ginseng, has antioxidant and neuroprotective activities and has been used as functional health food in Asian countries for many years. The aim of this study was to verify the protective effects of FG on chronic restraint stress (CRS)-induced learning and memory impairments as well as oxidative stress damage in mice.
Methods: Animals were subjected to object location recognition test (OLRT) and novel object recognition test (NORT) to evaluate discriminative ability and spatial learning and memory, and Morris water maze test (MWMT) was used to evaluate the acquisition and retention of spatial memory. In addition, oxidative stress parameters were assessed by measuring the malondialdehyde (MDA) and total antioxidant reactivity levels in serum.
Results: Experimental results demonstrated that CRS-induced mice exhibited significantly decreased discrimination index (DI) in OLRT and NORT, longer escape latency and swimming distance, and decreased crossing numbers in MWMT. FG (2 and 6 g/kg) treatment markedly enhanced the discriminative ability by elevating DI in OLRT and NORT, improved the acquisition and retention of spatial memory by decreasing escape latency and swimming distance in the acquisition phase, and increased the crossing numbers in the probe phase of MWMT. Administration of FG (2 and 6 g/kg) significantly reduced the elevated MDA level caused by CRS.
Discussion: Our results suggest that FG treatment could improve CRS-induced learning and memory impairments and oxidative stress damage. FG is an intriguing therapeutic agent and functional health food in stress-related dementia.
Keywords: Chronic restraint stress; Discrimination; Fresh ginseng; Oxidative stress; Spatial memory.