| This study was to investigate the optimal fermentation process of liquid fermentation of longan polysaccharide by Clostridium butyricum to increase the amount of viable bacteria of Clostridium butyricum and the total polysaccharide content in the fermentation broth.The UC mice model was used to test the drug intervention of the fermentation broth on ulcerative colitis.The first part explored the synergistic effect of fermentation of Clostridium butyricum and longan polysaccharide.The longan polysaccharide of dried longan meat were first extracted with enzymes,then the longan polysaccharide extract and the Clostridium butyricum were mixed and fermented.The effects of longan polysaccharide addition,inoculum size,fermentation time,and initial pH on the growth of Clostridium butyricum were evaluated by single-factor tests.Based on the results of single-factor experiments,L9(3~4)orthogonal test was designed to further optimize the fermentation process parameters.The results showed that the optimal fermentation process parameters for longan polysaccharides fermented by Clostridium butyricum were as follows:longan polysaccharide content 20%,inoculation volume 3%,fermentation time 16h,initial pH 7.0.The order of influence of the four factors on the fermentation process is:fermentation time>initial pH>longan polysaccharide addition amount>inoculum size.The validation test results showed that the amount of live bacteria of Clostridium butyricum in the fermentation broth could be maintained above 1.3×10~7 cfu/mL,and the polysaccharide content increased by 464.65 mg/mL on average compared with that before fermentation.The second part studied the drug intervention of broth on ulcerative colitis.First,the longan polysaccharide fermentation broth was obtained by fermentation of Clostridium butyricum and longan polysaccharide under the optimal fermentation process,and then the fermentation broth was applied to the UC mice model to study the effect of longan polysaccharide fermentation broth on body weight,colon length,DAL score,clinical score,colon tissue,serum levels of IL-6,IL-10 and TNF-?,colon intestinal flora in mice.The experimental results showed that mice in the model group lost body weight to 18.31g,the length of the colon was shortened to7.17 cm,the DAL score was 3.56,the clinical score was 5.33,and the histological injury score was 11.33,whereas the mice in the fermentation broth only lost 21.80g in body weight,the length of the colon was only shortened to 9.33cm,and the DAL score was 1.22.The clinical score was 1.67,histological injury score was 4.67,and all indicators were significantly lower than the model group.ELISA detection of mouse serum showed that the levels of IL-6,IL-10,and TNF-?in the model group were 34.63 pg/mL,29.71 pg/mL,and 37.62 pg/mL,respectively.The contents of IL-6,IL-10 and TNF-?in the serum of the fermentation broth group were 25.80pg/mL,34.68 pg/mL and 31.27 pg/mL,respectively,and there were significant differences compared with the model group.The high-throughput sequencing results showed that the fermentation broth significantly inhibited the relative abundance of pathogenic bacteria Helicobacter in the colon of mice.This study concluded that there is a synergistic effect between the fermentation of Clostridium butyricum and longan polysaccharide.That is,longan polysaccharide can promote the growth of Clostridium butyricum.The polysaccharide content in the fermentation broth is increased after the fermentation of longan polysaccharide by Clostridium butyricum.At the same time,longan polysaccharide fermentation broth has certain protective effect on DSS-induced UC mice.On the one hand,its mechanism of action may be related to its enhancement of anti-inflammatory factors and inhibition of proinflammatory cytokines which have produced anti-inflammatory effects.On the other hand,it may be related to maintaining the balance of the intestinal flora by inhibiting the relative abundance of pathogenic bacteria Helicobacter. |
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