Procyanidins from Lotus Seedpod Induce Apoptosis in HepG2 Cells via Caspase-dependent Pathway
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
The possible mechanism of apoptosis induced by procyanidins from lotus seedpod (LSPCs) in human hepatoma HepG2 cells was investigated. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to study the inhibitory effect of LSPCs on HepG2 cell proliferation, morphological changes in apoptotic nuclei were observed via Hoechst 33258 staining, and the percentage of apoptotic cells was calculated by double-staining flow cytometry using Annexin V conjugated to fluorescein isothiocyanate and propidium iodide. DNA damage, mitochondrial membrane potential, and expression levels of apoptotic proteins were determined by comet assay, JC-1 staining, and western blot, respectively. The results indicate that after treatment with LSPCs, HepG2 cell proliferation was significantly inhibited; there were obvious signs of apoptosis, including high chromatin condensation level, nuclear fragmentation, and karyopyknosis; and the number of chromatin-condensed cells increased from 3.86% to 42.76% (p<0.01). The percentage of viable cells decreased significantly and the proportion of apoptotic cells increased from 5.32% to 67.05% (p<0.01). Treatment with LSPCs caused DNA damage, loss of mitochondrial membrane potential, an increase in the protein expression levels of cytochrome C, caspase-3, and caspase-9, in addition to upregulation of Bax protein expression and downregulation of Bcl-2 protein expression. However, the apoptosis inhibitor Z-VAD reduced the inhibitory effect of LSPCs on HepG2 cell proliferation, significantly reduced nuclear condensation, inhibited mitochondrial damage and caspase protein expression, and eventually inhibited LSPC-induced apoptosis. Thus, the results show that LSPCs trigger apoptosis in HepG2 cells via the mitochondria-mediated, endogenous caspase pathway.
