Effects Of Lactobacillus Helveticus On Mucosal Immunity In Intestine Of Mice

Probiotics as one kind of lively organism exists in intestinal mucosa of lives.It has protective and modulatory effect to intestinal mucosa;also it is able to cure various intestinal diseases.Probiotics can act on host's immunity system,stimulate intestinal immunity and immune organ's growth such as thymus,spleen and bursa,it promotes macrophages' activity or exerts immunoadjuvants,at the same it can active the lymphoid tissue in intestinal mucosa and increase the secretion of SIgA.Probiotics plays immunoregulatory roles in humoral immunity and cellular immunity,it's mechanism of health care function becomes the important content in recent work.In this thesis we chose Lactobacillus helveticus TS206 as cultural bacterial,and systematically studied the effects of Lactobacillus helveticus TS206 on intestinal immunity in mice.First of all,we used improved bouillon medium to choose the appropriate medium for lactobacillus helveticus TS206,constituted the purification technology of bacterial cell with centrifugation and solution of protein,and then applied selective cultural technique to research intestinal microflora systematically,evaluated cytokines and SIgA in intestinal of mice with RIA and ELISA.We observed the infection of E.coli as well.The result demonstrated that,①the best culture medium for taking count of Lactobacillus helveticus TS206 is bromcresol green indicator culture medium.②the appropriate dose for feeding mice is 2×10~7cfu/d.③the effects of lactobacillus helveticus TS206 on SIgA in intestinal mucosa of mice for 15 days:the best tolerance time of mice to Lactobacillus helveticus TS206 is 10days,compared with control group the level of SIgA in Lactobacillus helveticus TS206 group is significantly higher(P＜0.01).The effects of lactobacillus helveticus TS206 on SIgA in intestinal mucosa of mice for 24 hours:the level of SIgA still rose in 24 hours after feeding mice with Lactobacillus helveticus TS206.④the effects of lactobacillus helveticus TS206 on cytokine in intestine of mice for 15 days:compared with control group the level of four cytokine in mice's intestine of lactobacillus helveticus TS206 group is higher(P＜0.05), before the third day the value of Th1 type cytokine(IL-2,IFN-γ)was up to their top,and the value of Th2(IL-4,IL-6)reached to the maximum at the fifth day,the proportion of Th1 T cell and Th2 type T cell in intestine of mice was very normal.The effects of lactobacillus helveticus TS206 on cytokine in intestine of mice for 24 hours:the value of IL-2 and IL-6 reached to the maximum at the sixth hour,the level of IL-4 was up to its highest degree at the first hour,and IFN-γobtained its top at the third hour.The value of IFN-γ/IL-4 is lower in probiotics group,it may be because the different differentiation of T cell.Compared with long time-feeding group(15 days) the cytokine of the short-feeding group(24 hours)fluctuated more serious,so the long-feeding group is more suitable to reflect the regulation of lactobacillus helveticus TS206 to mice's intestinal mucosa immune.Thus we can evaluate the immune role of lactobacillus helveticus TS206 more deeply.