쥐 해마의 발달과정에서 N-methyl-D-aspartate 신경독성과 N-methyl-D-aspartate 수용체 2B 서브유닛의 발현양상

Abstract

Background: The developing brain has a distinctive set of characteristics that make it have different susceptibility to excitotoxins. Using primary tissue cultures of rat hippocampus, we investigated the developmental susceptibility to N-methyl-D-aspartic acid (NMDA)-induced cell death at various days in vitro in relation to the appearance of Bcl-2 protein and NMDA receptor 2B subunit. Methods: Six, 12, and 18 days-in-vitro (DIV) hippocampal tissue cultures derived from 7-day-old Sprague-Dawley rat pups were used. Each group was treated with 100 μM NMDA in 5% CO2 incubator at 36℃ for 30 min. A western blot was then performed for the NeuN, Bcl-2 and NMDA receptor 2B subunit and propidium Iodide (PI) staining. Results: The NeuN and Bcl-2 were most highly expressed in 12 DIV tissues. The reductions of the NeuN and Bcl-2 protein expressions by NMDA were significant at the 12 and the 18 DIV tissues, but less at 6 DIV tissues (p<0.05). The PI staining showed that the area of fluorescence of the 7 DIV tissues after NMDA exposure was less than the DIV 13 and 19 tissues. Without NMDA treatment, the NMDA receptor 2B subunit protein expressions at the 6 DIV tissues were highest and decreased with maturation. Conclusions: These results suggest that the immature tissues were more resistant to NMDA toxicity than the mature tissues, and further studies are needed to establish its relationship with the Bcl-2 protein and NMDA receptor 2B subunit.