In vitro effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 cells

AIM： To investigate the effects of chitosan nanoparticles on proliferation of human gastric carcinoma cell line MGC803 in vitro and the possible mechanisms involved. METHODS： Chitosan nanoparticles were characterized by particle size, zeta potential, and morphology. After treatment with various concentrations of chitosan nanoparticles （25, 50, 75, 100 μg/mL） at various time intervals, cell proliferation, ultrastructural changes, DNA fragmentation, mitochondrial membrane potential （MMP）, cell cycle phase distribution and apoptotic peaks of MGC803 cells were analyzed by MTT assay, electron microscopy, DNA agarose gel electrophoresis, and flow cytometry. RESULTS： Chitosan nanoparticles exhibited a small particle size as 65 nm and a high surface charge as 52 mV. Chitosan nanoparticles markedly inhibited cell proliferation of MGC803 cells with an ICso value of 5.3 μg/mL 48 h after treatment. After treatment with chitosan nanoparticles, the typical necrotic cell morphology was observed by electron microscopy, a typical DNA degradation associated with necrosis was determined by DNA agarose electrophoresis. Flow cytometry showed the loss of MMP and occurrence of apoptosis in chitosan nanoparticles-treated cells. CONCLUSION： Chitosan nanoparticles effectively inhibit the proliferation of human gastric carcinoma cell line MGC803 in vitro through multiple mechanisms, and may be a beneficial agent against human carcinoma.

Effects of dietary fresh fermented soybean meal on growth performance, ammonia and particulate matter emissions, and nitrogen excretion in nursery piglets

This study was conducted to investigate the effects of fresh fermented soybean meal（FSM） on the growth performance of nursery piglets, nitrogen excretion in feces, and the concentrations of ammonia（NH3） and particulate matter（PM） in the piggery. A total of 472 nursery piglets（Landrace×Yorkshire,（16.3±0.36） kg body weight） were randomly allocated into two treatments with 236 pigs in each treatment. The pigs were fed the basal diet without fresh FSM（control） or diet containing 10%（100 g/kg） fresh FSM（FSM group）, and the crude protein content of the two groups was consistent. The feeding trial lasted for 28 d. The results showed that the pigs fed fresh FSM had increased（P〈0.05） average daily gain（ADG） compared with the control. There was no significant difference（P〈0.05） in feed to gain ratio（F：G） between the two groups. During the whole experiment, the concentration of NH3 in the piggery decreased（P〈0.05） by 19.0%, and the concentrations of PM（PM（10） and PM（2.5）） in the piggery decreased（P〈0.05） by 19.9% and 11.6%, respectively, in the FSM group, compared with the control. The ammonia nitrogen and nitrite content in feces increased（P〈0.05） by 32.9% and 28.4%, respectively, in the FSM group. The fecal p H declined（P〈0.05） significantly in the FSM group compared with the control. At the end of experiment, total protein（TP） concentration was increased（P〈0.05） significantly and blood urea nitrogen（BUN） concentration was decreased（P〈0.05） for pigs fed the diet with fresh FSM. The results indicated that dietary fresh FSM not only improved the growth performance of nursery piglets, but also reduced the NH3 concentration in the piggery due to nitrogen conversion, and decreased the concentrations of PM（10） and PM（2.5） in the piggery.