Apoptosis-promoting effect of Panax notoginseng extracts on MNNG-transformed GES-1 cells

Abstract

To study the apoptosis-promoting effect of the serum from Panax notoginseng extracts-fed dog on precancerous gastric cells by means of flow cytometry. In the experiment, we adopted eternalized human gastric mucosa epithelium GES-1 cells transformed by N-methyl-N'-nitro-N-nitroso-guanidine (MNNG) (MC cells) as the model of precancerous lesions for study in vitro. We took the serum of a dog before and at two different points of time (2 and 6 hours) after feeding the dog with Panax notoginseng extracts for experiment. The MC cells were cultured in mediums with different concentrations of the medicated serum at 2- or 6-hour point of time for 72 hours. By means of flow cytometry, we examined the apoptosis-promoting effects of the serums on the MC cells. The medicated serums at these 2 points of time had significant effects in promoting MC cell apoptosis. The proportions of apoptotic cells in culture mediums with medicated serums had a significant increase as compared with those in culture mediums with non-medicated serums (serum obtained before administration of extracts to the dog) under the same conditions (P<0.05). The number of MC cells in G(0)/G(1)phase was decreased (P<0.05) and that in G(2)/M phase increased (P<0.05), while no consistent changes were observed in S phase. The medicated serums obtained at the two different points of time have significant apoptosis-promoting effects on MC cells. They decrease the number of MC cells in G(0)/G(1) phase and increase the number of MC cells in G(2)/M phase. This is probably responsible for the effects of Panax notoginseng extracts in inhibiting the proliferation of MC cells and promoting its apoptosis.