Regulation Of Substance P And Vasoactive Intestinal Peptide In Local Intestinal Mucosal Immunity Of The Sacculus Rotundus Of Rabbits

To investigate the mechanism of substance P (SP) and vasoactive intestinal peptide (VIP) in the mediation of intestinal mucosal immunity and the interplaying of SP, VIP with immune related cells, the distribution and expression of SP, SPmRNA, VIP, CD25, CD68, Lysozyme and anti-bacterial peptide(ABP) in the Sacculus Rotundus(SR) of rabbits were investigated using tissue culture methods, immunohistochemistry, in situ hybridization, immune electron cytochemistry, tissue micro-arraying and image analysis during the early stage of the rabbits were infected with Pasteurella and E. coli. and the cultural tissues of SR were stimulated by the same pathegons. The results were showed as followed:1. The expression of SP, VIP in some subfields of sacculus rotundus altered markedly after the rabbits were inoculated with Pasteurella and E.coli. At the same time, the numbers of activated lymphocytes, macrophages, DNES cells and the expression of Lysozyme also up-regulated in some subfields of sacculus rotundus. There were correlated relations between SP expression and the numbers of macrophges, DNES cells, CD25-expressing lymphocytes in some extent.2. When it was stimulated by the Pasteurella and E. coli in vitro, the tissue of SR up-regulated expression of SP greatly and down-regulated the expression of VIP markedly. Meantime, the expression of SYP, CD25, CD68, lysozyme, and ABP increased markedly. There's a close correlationship between the SP, VIP expression and CD25, CD68, SYP expression.3. The SP mRNA was up-regulated markedly in in-vitro experiments and no such results were found in the in-vivo experiments.4. When the cultural fliud were added into the antibodies of SP, the activation and the expression of CD68, SYP were inhibited somehow. Meanwhile, the antibodies of VIP enhanced the activation of lymphocytes and the expression of CD68, SYP in sacculus rotundus. The added SP can upregulate expression of CD25, CD68 and downregulate SYP to some extent in the tissue of SR.5. The ultrastructures of the SP, VIP secretory cells showed there were several kinds of cells with different morphology which could express these neuropeptides in sacculus rotundus. Some intercellular immunoreactive products and cells with immunoreactive membrane (including lymphocytes, macrophages, etc.) were found in the SR, which might favour the transduction of these two peptides.The results suggested that SP, VIP may play an important role in the regulation of intestinal mucosal immunity by mediating of the activation of lymphocytes, the macrophages and DNES cells. VIP displayed downregulating effect in these reactions somehow. SP and VIP may be a couple moleculars with reversed function in the regulation of local intestinal mucosal immunity.The characteristics of immune reaction of SR and the mechanism of SP, VIP in SR which involved in the regulation of the intestinal mucosal immunity were discussed in this study, which richer the datafor the immnuo-neuro-endocrine network theory and provided some new knowledge for reference of making new strategy to control the disease of intestinal bacterial infection.