Catalpol protects primary cultured cortical neurons induced by Abeta(1-42) through a mitochondrial-dependent caspase pathway.

It has been reported that catalpol, an iridoid glucoside, isolated from the root of Rehmannia glutinosa, protected cells from damage induced by a variety of toxic stimulus such as LPS, MPP(+) and rotenone. Here, we further evaluated the effect of catalpol against Abeta(1-42)-induced apoptosis in primary cortical neuron cultures. In the present study, the primary cortical neuron culture treated with Abeta(1-42) was severed as cell model of Alzheimer's disease (AD) in vitro. By exposure to Abeta(1-42) (5 microM) for 72 h in cultures, neuronal apoptosis occurred characterized by enhancement of activities of caspases and reactive oxygen species (ROS) as well as Bax increase, loss of mitochondrial membrane potential and cytochrome c release. Pretreatment with catalpol (0.5mM) for 30 min prior to Abeta(1-42) treatment attenuated neuronal apoptosis not only by reversing intracellular ROS accumulation, Bax level, mitochondrial membrane potential and, cytochrome c release to some extent, but also through regulating the activity and cleavage of caspase-3 and caspase-9. Thus, catalpol protects primary cultured cortical neurons induced by Abeta(1-42) through a mitochondrial-dependent caspase pathway.