Propofol Promotes Proliferation of Cultured Adult Rat Hippocampal Neural Stem Cells

Abstract

The effect of propofol on proliferation of adult neural stem cells (ANSCs) is unclear. We investigated the effect of propofol on cultured rat ANSCs and the underlying molecular mechanisms, especially the role of activated cAMP response element binding protein (CREB). Rat ANSCs were treated with propofol at concentrations of 0 (control), 10, 50, or 100 μM, or with a DMSO vehicle. The cell viability was checked by cell counting and MTT assay. The proportions of BrdU-positive cells and pyknotic nuclei were also checked. Caspase activity was measured by a colorimetric assay. Cytoplasmic [Ca] were determined with Fura2-AM. The expression of CREB and phospho-CREB in cells was examined by immunostaining and Western blot. The role of p-CREB in cell proliferation was confirmed by using KN93, an inhibitor of p-CREB formation. Propofol promoted the proliferation of ANSCs (P<0.01) and increased the proportion of BrdU-positive cells (P<0.01). Cell death was maintained at a low level (P=0.0691) and inhibition of caspase-3 activity with propofol was not significant (P=0.0839). Propofol elevated the cytoplasmic-free calcium concentrations in ANSCs (P=0.0057). CREB and phospho-CREB were generally expressed in ANSCs with or without application of propofol. Propofol upregulated the phosphorylation level of CREB in ANSCs (P=0.0074). Application of KN93 diminished the proliferative effects of propofol and p-CREB levels (P<0.01) without disturbance of intracellular [Ca] (P=0.0722). Propofol acts partly through a Ca-mediated pathway to enhance CREB phosphorylation. We believe this mechanism promotes the in vitro proliferation of ANSCs.