Objective: To investigate the effects of extracts from Renshen (Radix Ginseng), Sanqi (Radix Notoginseng), and Chuanxiong (Rhizoma Chuanxiong) on the endothelial actin cytoskeleton in senescent human cardiac microvascular endothelial cells (HCMECs), and to propose the possible mechanism underlying the actions.
Methods: Lentiviral mediated RNA interference was applied to a replicative senescent HCMEC model by knocking down heat shock protein 27 (HSP27) gene. Cells were treated with extracts from Renshen (Radix Ginseng), Sanqi (Radix Notoginseng), and Chuanxiong (Rhizoma Chuanxiong) at final concentrations of 50, 100, and 200 mg/L, respectively and with 10 μM resveratrol for 48 h. Untreated cells were used as controls. Senescence was detected by senescence β-galactosidase staining and cell proliferation was analyzed by cell counting kit-8 assays. Secreted nitric oxide levels were detected by nitrate reductase. Morphological changes of F-actin and G-actin were observed by laser scanning confocal microscopy. Protein and gene expression of F- actin and HSP27 was detected by western blotting.
Results: Compared with the control group, the proportion of senescent HSP27 shRNA cells treated with the extracts was decreased and their proliferation was increased. In the extract intervention group, F-actin around the cell periphery became irregular and jagged fractures formed gradually and then dissipated. Moreover, some dynamic actin stress fiber filaments appeared. The G-actin stretched to the cell periphery and punctate staining was scattered in the cytoplasm. In addition, the mean optical density value of F/G-actin was decreased significantly and the protein expression of F-actin was downregulated.
Conclusion: The extracts delayed microvascular endothelial cell senescence by downregulating the expression of F-actin through HSP27.
Keywords: Actincytoskeleton; Aging; Chuanxiong (Rhizoma Chuanxiong); Endothelialcell; HSP27 heat-shock protein; Renshen (Radix Ginseng); Sanqi (Radix Notoginseng).