The Research Of Astragalus Polysaccharides On Chronic Atrophic Gastritis And Precancerous Lesions Of Gastric Cancer

Chronic Atrophic Gastritis (CAG) is a process of chronic inflammation of the stomach mucosa, leading to loss of gastric glandular cells induced by lots of reasons. CAG with intestinal metaplasia and dysplasia were considered as precancerous lesions of gastric cancer(PLGC), which is an important process in normal gastric mucosa into gastric cancer.So it is important to make research on CAG and PLGC. Radix Astragali is the dried root of Astragalus membranaceus (Fisch.) Bge, var. mongholicus (Bge) Hsiao and Astragalus membranaceus (Fisch.) Bge.,sweet,Astragalus has been used in traditional Chinese medicine, usually in combination with other herbs, to support and enhance the immune system. It is still widely used in China for chronic hepatitis and as an adjunctive therapy for cancer. It is also used as a folk or traditional remedy for colds and upper respiratory infections, and for heart disease. As the main active components of Astragalus, Astragalus Polysaccharides(APS) have been extensively studied because they exhibited superior immune enhancement effects,and its effect of anti-viral, anti-tumor, anti-stress, anti-oxidation were also reported.In this study,the model of CAG rats were established and evaluated in part1;Part2,to observe the effect of APS on CAG rats after giving APS.For further reaserach on the effect of APS, gastric cancer cells were cultured in vitro to observe the effect of APS on cell proliferation and cell cycle in gastric cancer cells.Part1The establishment of model of CAG ratsTo setablish the model of CAG,Rats were administered MNNG and then allowed water with MNNG stored in black bottles ad libitum for12weeks. As promoting inducers, rats were also given40%alcohol twice a week and an irregular diet with fasting or repletion intervals.During this periods, the body weight, general behavior and food consumption of rats were checked, and the samples of stomachs were removed to observe the pathological change of rats weekly. The reseults showd that the body weight of CAG rats increased much more slowly than that of the control group, food consumption decreased obviously, gastric mucosa epithelial degeneration, lamina propria lymphocytes, plasma cell infiltration, glandular atrophy and mucosal erosion, and local intestinal metaplasia. Part2Effect of APS on CAG ratsFrom the fifth week,rats were given APS, the body weight, general behavior and food consumption of rats were checked weekly, and the samples of stomachs were removed to observe the pathological change of rats.To observe change of gastrointestinal hormone of gastrin (GAS), somatostatin (SS) and motilin (MTL); To observe change of gastric mucosal damage factor of endothelin(ET), nitric oxide synthase(NOS) and Prostaglandin E2(PGE2); To observe change of gastric mucosal protect factor of secretory immunoglobulinsA(sIgA), oxidized glutathione(GSSG) and reduced glutathione(GSH); To observe the expression of matrix metalloproteinase2(MMP-2),epidermal growth factor receptor(EGFR), cyclooxygenase2(COX-2). The results showed that APS could increase the body weight and food consumption of rats, improve gastric lesions, reduce the infiltration of inflammatory cells as well as ulcer or erosion formation;APS could also regular the balance of gastrointestinal hormone,significantly increase level of GAS and SS in CAG rats, while MTL level had no significant change;APS could decrease level of gastric mucosal damage factor of ET, NOS and PGE2,while increasing level of sIgA and GSH,and rate of GSH/GSSG;And APS decreased the expression of COX-2、 MMP-2、EGFR.Part3Effect of APS on cell proliferation and cell cycle in gastric cancer cells Subculture was carried on by Human Gastric Carcinoma Cell Line MKN45and MGC-803in RPMI1640culture solution. MTT assay was used to determine the inhibitory effect of Astragalus Polysaccharides on the growth of MKN45and MGG-803cells. The changes of cell cycle of MKN45and MGC-803were detected by flow cytometry. MTT assay show that Astragalus Polysaccharides could inhibit the proliferation of cell line MKN45and MGC-803,cell cycle analysis indicated that Astragalus Polysaccharides can arrest MKN45and MGC-803at G0/G1phase,both of them were time-and dose-dependent manner.:Astragalus Polysaccharides can inhibit proliferation of gastric carcinoma cells,and it can arrest cell cycle of G0/G1phase may be one of the mechanisms.