Objective: To explore whether edaravone protects cells damage via mitogen-activated protein kinases (MAPKs) signal pathway, and which procedure of p38 be affected so as to add theories for AD pathogenesis and treatments.
Methods: According to different drugs treated, PC12 cells in vitro were divided into four groups. Negative control group: cells were treated with media alone. AD model group: cells were treated with 30 pmol/L Abeta(25-35). Inhibitor control group: cells were treated with 10 micromol/L SB203580 Cp38 mitogen-activated protein kinase (p38) inhibitor], 10 micromol/L SP600125 [c-Jun NH2 terminal kinase (JNK) inhibitor], or 10 micromol/L PD98059 extracelular signal regulated kinase (ERK) inhibitor]. Low-dose, middle-dose and high-dose edaravone group: cells plated for 24 hours treated with 30 micromol/L Abeta(25-35) and co-treated with 20, 40, 80 micromol/L edaravone 3 hours, respectively. The morphology of the treated cells were observed, the p-p38, p-JNK and p-ERK proteins in each group were tested by the Western blot. The p38 mRNA were tested in each group above (only add SB203580 10 micromol/L in third group) by the real time PCR.
Results: (1) The p-p38 protein was significantly increased in model control group compared with that in negative control group (P<0.05). The p-p38 protein in the inhibitor group and edaravone groups was decreased significantly (P<0.05) when compared with that in model control group. The p-p38 proteins were significantly increased in the three edaravone groups compared with that in inhibiter control group (P<0.05). The p-p38 protein in middle-dose edaravone group was decreased compared with that in low-dose edaravone group (P<0.05). There was no relationship in dose-dependent manner about edaravone. Compared with three edaravone groups, the p-p38 protein was lower than it in high-dose edaravone & inhibiter group (P<0.05). (2) The p-JNK protein was significantly increased in model control group compared with that in negative control group (P<0.05). The p-JNK protein in the inhibitor group was decreased compared with that in model control group (P<0.05). (3) No significantly difference of p-ERK protein concentration was observed in other groups when compared with that in negative control group (P>0.05 each). (4) Compared with negative control group, the p38 mRNA in model control group was significantly increased, and it was significantly decreased in inhibitor control group (P<0.05 each). In 40 micromol/L and 80 micromol/L edaravone groups, the p38 mRNA was significantly decreased compared with that in model control group, and it still was decreased compared with that in inhibitor control group (P<0.05). The p38 mRNA in 40 micromol/L edaravone group was the lowest among three edaravone groups, and it was obviously different from that in 20 micromol/L and 80 micromol/L edaravone groups (P<0.05).
Conclusion: Abeta(25-35) could increase the p-p38 and p-JNK protein expression in cultured PC12 cells, but there was no obviously expression of p-ERK protein. These indicated that Abeta(25-35) might activate MAPKs signal pathway, especially p38 and JNK, and lead to PC12 cell damage. Edaravone could decrease p38 mRNA induced-Abeta(25-35), which indicated edaravone could protect PC12 cell damage via blocking p38 signal pathway in mRNA stage and protein stage simultaneously. Hence, it is promising that edaravone would be a new medicine for AD.