Protective Effects Of L.plantum And E.coli Cell Wall Peptidoglycan Sustained - Release Microspheres On Intestinal Flora And Organism In Mice

The biological activities of peptidoglycan are getting more and more attention. This thesis aims to compare the effects of microencapsulated peptidoglycan from gram positive bacteria(represented by L.plantum) and gram negative bacteria(represented by E.coli) on intestinal flora and systematics immunity, whereby providing experimental data for potential vaccine development of peptidoglycan.E.coli peptidoglycan was separated by trichloroacetic acid method, with(11.2±1.35) % extraction yield. E.coli prptidoglycan(EPG) microspheres was prepared by chemical crosslinking process using chitosan as wall materials. Scanning electronic microscopy(SEM) results showed good spherity EPG microspheres. This microspheres has laoding capacy of(43.51±4.66)g/100 g and encapsulation rate at(91.20±1.82)%.The results from regulation effects of peptidoglycan microsphere on mouse intestinal flora and immune fuction showed that the number of probiotic flora such as lactobacillus and bifidobacterium in the intestinal tracts from mouse treated with peptidoglycan microspheres is significantly higher than those from saline-treated group(P<0.01); and conditional pathogenic bacteria such as enterobacter and enterococcus were significantly lower than those in normal saline group(P<0.01). Contents of serum lysozyme, IgG and SIgA, liver and spleen indexes were significantly higher in peptidoglycan microspheres-treated group than those in normal saline group(P<0.01),The protection effects of peptidoglycan microspheres against the E.coli infected mouse showed that the number of healthy-promoting bacteria in the intestinal tracts from peptidoglycan microsphere-treated mouse was significantly higher than those in normal saline-trated group(P<0.01); the number of conditional pathogenic bacteria was significantly lower than those in normal saline-trated group(P<0.01). Serum IgG, IL-10 contents and SIgA levels in intestinal mucosa were significantly higher than thosein normal saline-treated group(P<0.01), while the IL-6 content was significantly lower than in normal saline group(P<0.01),This study shows that the E.coli peptidoglycan microspheres have such features as good shape, stability. Peptidoglycan microspheres from both stain can regulate intestinal flora and systimetic immune function. The intestinal flora imbalance and malfunction caused by E.coli infection can also be alleviated by the peptidoglycan microspheres, and no differences were found for the protective effects from both strain-derived peptidoglycan. Preliminary results reveal that there is non-specific protection effects, which set basis for further exploration of the peptidoglycan-based vaccine.