Abstract:

Objective   To investigate the activations of phosphorylation of p38MAPK(P-p38MAPK) and caspase-3 in cultured cortical neurons after NMDA injury and the protective effect of SB203580. Methods   Primary cortical neurons cultured for 7d were randomly divided into 5 groups: the control group, the NMDA group and low， medium and high doses of SB203580 groups. The cortical neurons were pre-cultured with regular media including different doses of SB203580 (5,10 and 20μmol/L) for 24h before being exposed to NMDA (50μmol/L). MTT assay was used to evaluate cell survival. Apoptotic cortical neurons were examined using acridine fluorescent staining. Content of lactic dehydrogenase(LDH) was detected. P-p38MAPK and caspase-3 protein expressions were detected by immunocytochemical(IHC) staining and Western blot (WB). Results   Compared with the control group, the OD value of the NMDA group was significantly increased(P<0.01), while it was decreased in the low, medium and high dose groupsof SB203580(P<0.05),  and apoptotic cortical neurons were significantly increased in the NMDA group(P<0.01). Compared with the NMDA group, the number of apoptotic cortical neurons was decreased in SB203580 groups(P<0.05). Content of  LDH was significantly increased in the NMDA group compared with the control group, (P<0.01)， while it was significantly decreased in SB203580 groups compared with the NMDA group(P<0.05). Expressions of P-p38MAPK and caspase-3 in cultured neuron were remarkably up-regulated in the NMDA-induced group than in the control group, while they were significantly down-regulated in SB203580 groups than in the NMDA group (P<0.05 or P<0.01). Conclusion   P-p38MAPK and caspase-3 are activated in cultured cortical neurons after NMDA-induced injury, and SB203580 has a protective effect through activation of P-p38MAPK and down-regulation of caspase-3.

Key words: Phosphorylation of p38mitogen-activated protein kinase; Caspase 3; Receptors, N-methyl-D-aspartate; Apoptosis