Effects Of Chiral 3-n-butylphthalide On Neuronal Apoptosis Induced By Transient Focal Cerebral Ischemia In Rats

摘要

The effects of 3-n-butylphthalide (NBP) on neuronal apoptosis were studied in transient focal cerebral ischemia rats. The action potency of (-)-, (+)- and (?- NBP was compared, and the enantiomer that played a main role was clarified. Using the terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) assay and gel electrophoresis, significant DNA fragmentation was detected at 24 hours after 2 hours of middle cerebral artery occlusion (MCAO). This response was dose-dependently inhibited by (-)- NBP (5, 10 mg/kg i.p.). (-)- NBP 10 mg/kg almost completely inhibited DNA fragmentation, whereas (+)- NBP 10 mg/kg showed less effect. (?- NBP (20 mg/kg) showed an inhibitory effect between that of (-)- NBP (10 mg/kg) and (+)- NBP (10 mg/kg). During the apoptotic process, cytochrome c was released into the cytosol and caspase-3 was activated, as demonstrated by Western blot analysis and immunohistochemistry. This effect was markedly inhibited by (-)- NBP, indicating that the antiapoptotic effect of (-)- NBP might partially be mediated by reducing cytochrome c release and caspase-3 activation. The action potency of (+)- and (?- NBP on the changes of cytochrome c and caspase-3 protein was similar to that on DNA fragmentation. The results indicated that (-)- NBP played a main role on inhibiting apoptosis and it might have the potential to be a new antiapoptotic candidate for the treatment of ischemic cerebrovascular and neurodegenerative diseases. Introduction (-)- 3-n-butylphthalide [(-)- NBP] was extracted as a pure component from seeds of Apium graveolens Linn (1). Then, (±)- NBP was synthesized and developed as an anti-cerebral ischemic agent. There is a chiral center in the molecule of NBP, and a pair of enantiomers were synthesized (Figure 1).