Optimization Design,Stability Evaluation And Application Of Bionic Large Intestine Reactor

Compared with traditional animal experiments and human clinical experiments,the in vitro model reactors have the characteristics of good reproducibility,high visualization,simple operation etc.,and no ethical restrictions.Therefore,it has become a trend to use in vitro model reactors to study food,drugs and intestinal flora.In recent years,domestic and foreign scientific research team have devoted themselves to developing new types of reactors that can simulate the physiological functions and dynamic characteristics of the gastrointestinal tract,and have a highly bionic structure.However,at present,in vitro model reactors are mostly monopolized by foreign countries,which are expensive and difficult to maintain after sale.However,domestic reactors started late,with low bionic level and mostly rigid structures.In response to this problem,this paper optimized and designed a bionic large intestinal reactor(BLR)based on the gastrointestinal simulation reactor(GSR),verified the stability of the BLR,and it was initially applied to the evaluation of the function of low glutelin rice.The main contents and results are as follows:(1)BLR adopted new connection methods,dialysis methods,sampling methods,and membrane forming methods,and optimizes tank dimensions,materials and some procedures.The use of seals for connection made the connection of the reactor easier and better airtight;the dialysis bag was used to simulate the absorption of small molecular substances,which avoided contamination caused by bacteria flowing into dialysate;the location of the sampling port was designed at the top and used a luer valve made of high temperature resistance and strong acid and alkali resistance material to avoid contamination during sampling;the improvement of the film-making method and the film-making mold made the film-making efficiency higher,the film thickness was more uniform,the film strength was greater,and the bubble was less;the tank size was improved to avoid damage caused by excessive stretching of the silicone film;the material of some parts was replaced with polytetrafluoroethylene which was resistant to high temperature and high pressure and strong acid and alkali,so as to avoid the phenomenon of slippery wire;part of the program was improved to to control the feeding rate and dialysis rate.(2)The gel fragments of different concentrations were crushed in BLR,and the crushing effect was compared with the crushing effect of magnetic stirring and water bath shaking,and it was found that BLR has a stronger ability to crush semi-solids;in order to verify that BLR can be suitable for the fermentation and culture of anaerobes,facultative anaerobes and mixed bacteria.Bifidobacterium animalis,Bacillus cereus and Fecal bacteria were successively fermented and cultured for 7 days in BLR,the concentration of the flora and the content of metabolites can be kept stable for a long time.The analysis of metabolites shows that throughout the fermentation process,the flora has maintained a healthy state.By comparing with the anaerobic tube level,it was proved that BLR can be more superior than anaerobic tube.(3)BLR also has the function of simulating digestion in the stomach and small intestine.The relative soluble protein content and starch digestibility of low gluten rice were determined by BLR simulation digestion.The undigested part of low gluten rice was fermented in BLR to the Akkermansia muciniphila and fecal microorganisms of healthy people,and compared with starch and ordinary rice group.The measurement of the bacterial concentration and the content of metabolites after 72 h of fermentation showed that compared with starch and ordinary rice,low gluten rice can promote the production of short chain fatty acids(SCFAs)and lactic acid by Akkermansia muciniphila and intestinal flora.It has a certain degree of inhibitory effect on some bad metabolites,such as branched chain fatty acids(BCFAs)and ammonia production.And it can promote the growth of the number of Akkermansia muciniphila.For the intestinal flora,it can increase the number of beneficial intestinal bacteria.such as Bifidobacteria and Bacteroides,reduce the concentration of harmful bacteria,such as Fecal coliform.According to 16 S r DNA sequencing,low gluten rice can significantly increase the relative abundance of intestinal flora,especially the relative abundance of some beneficial intestinal bacteria,such as Bacteroides and Firmicutes,and reduce the relative abundance of harmful bacteria in the gut,such as Proteobacteria and Fusobacteria.