Anticonvulsant and anti-apoptosis effects of salvianolic acid B on pentylenetetrazole-kindled rats via AKT/CREB/BDNF signaling

Abstract

Neuronal apoptosis is a regulated intrinsic cell mechanism and common pathological phenomenon after seizures, which involves the protein kinase B/cAMP response element binding protein / brain derived neurotrophic factor (AKT/CREB/ BDNF) signaling pathway. In this study, we aimed to identify the effects of salvianolic acid B (Sal B), a major water-soluble component of the Chinese herb, Danshen, on rats in which seizures had been induced by pentylenetetrazole (PTZ) and the underlying molecular mechanisms mediating these effects. For this, 60 adult male Sprague-Dawley rats were divided into a control group, a 'PTZ' group and a 'PTZ + Sal B' group. The animals in the control group received an intraperitoneal (i.p.) injection of saline on alternate days for a total of 15 injections and saline orally once a day for 29 days. The animals in the 'PTZ' group received PTZ (40 mg/kg, i.p.) on alternate days for a total of 15 injections and saline orally once a day for 29 days. Similarly, the animals in the 'PTZ + Sal B' group received PTZ (40 mg/kg, i.p.) on alternate days and Sal B (20 mg/kg) orally once a day for 29 days. Neural density was then evaluated using immunofluorescence (IF) staining of microtubule-associated protein 2 (MAP2). Neuronal apoptosis was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. In addition, the expression of several proteins related to AKT/CREB/BDNF signaling was measured using Western blotting. The results indicated that more severe seizures, decreased neural density, decreased expression of Bcl-2, increased expression of Bax and cleaved caspase-3, and inactivation of AKT/CREB/BDNF signaling occurred in the 'PTZ' group in comparison with the control group. However, those changes were suppressed by Sal B. Thus, these data suggest that Sal B has anticonvulsant and anti-apoptotic effects in a PTZ-induced seizure model through activation of the AKT/CREB/BDNF signaling pathways.

Keywords: AKT/CREB/BDNF signaling; Epilepsy; Neuronal apoptosis; Salvianolic acid B.