| Summary: | The aim of this study was to investigate the oxidative and proliferative effects of grape seed extract (GSE). Piglet intestinal epithelial cells (IPEC1)
were selected as an unstressed cell model, or they were exposed to 400 μM H2O2 to establish a H2O2-stimulated cell model. The glutathione
(GSH) and total antioxidant capacity in response to GSE addition were tested in the unstressed and H2O2-stimulated cell models. The relative
mRNA levels of antioxidant or antioxidant enzymes and apoptosis-related genes were measured by Real-Time RT-PCR. In the unstressed status,
the cell survival ratio and GSH increased with the addition of GSE at 1 and 10 μg/mL but diminished at 60 μg GSE/mL. The addition of 1 μg/mL
GSE upregulated the mRNA expression levels of B-Cell Lymphoma protein-2 (Bcl-2), cysteine aspartases-3 (Caspase-3), cysteine aspartases-8
(Caspase-8) and glutathione peroxidase-1(GPx-1), while it downregulated that of Bcl2-associated X protein (Bax), copper-zinc superoxide
dismutase, glutathione S-transferase (GST), thioredoxin, thioltransferase and thioredoxin reductase. As GSE reached 60 μg/mL, the tumor protein
p53 (p53) and caspase-8 gene expressions were upregulated. In stressed status, 1 and 10 μg GSE/mL promoted the increase of GSH. H2O2-
induced increases in Bax, p53, and Caspase-3 mRNA expressions were attenuated by the subsequent addition of 1 μg GSE/mL and promoted the
gene expression of tumor necrosis factor-α, GPx-1 and thioltransferase (Ttas). Treatment with 60 μg GSE/ml resulted in a significant reduction in
Bax, p53, manganese superoxide dismutase and GST mRNA expressions. These results indicate that GSE exhibits antioxidative and proliferative
functions on unstressed IPEC1 cells at low and medium levels and oxidative and antiproliferative functions at high levels.
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