The Effect of Glycine max Extract Diets on Changes in NR2B Gene Expression, Cognitive Vitality and Neurotoxicity in High Concentrate Consumption

Abstract

The effects of soybean extract (Glycine max) on NR2B expression, cognitive vitality and neurotoxicity have not been exclusively reported. Here, we examined the correlation between Glycine max concentration and the N-methyl-D-aspartate (NMDA) receptor NR2B. We observed the brain weight, bodyweight and body movement in animals that received soybean extract in their food. Brain tissues from five groups of rats treated with five different concentration of soybean extract (5-50% of total diet calories) were collected. Rats without treatment served as the control group. NR2B expression was determined using RT-PCR. Average values of escape latency (EL) on day four in the control. 5%, 10% and 20% groups were 34.5, 29.67, 27.2 and 33.83 seconds, respectively. The EL of the 10% group was significantly shorter than that of the control. The low (5-10%) and moderate (20%) extract concentrations were not found to induce any abnormality in body movements, whereas the high concentration (40-50%) groups were found to have some movement disorders after four weeks of administration. The cerebellum weight of the high concentration group (50%) was decreased 18% from the pre-treatment weight, and this decrease might be related to the movement abnormality, which was possibly due to a defect of the CNS in this group. Specifically, we speculated that this abnormality might be due to damage in the cerebellum. These events might be initiated by an increase of NR2B as an adaptive process in the low and high soybean extract groups (5-40%), followed by a sudden decrease in NR2B in the 50% group due to the possibility of brain injury. The low percentage Glycine max extract diet (<5%) is recommended, and 5-10% can be tolerated, but more than 20% is not recommended. High concentrations (40-50%) of soybean extract were found to have neurotoxicilogical effects.