| Background Multiple organ dysfunction syndrome (MODS) is the main cause of the death of patients with abdominal surgical diseases. The gastrointestinal tract as a reservoir of bacteria and considered to be the trigger and target site of systemic inflammation response syndrome (SIRS) and MODS. The condition of gastrointestinal function is also thought to be the important criterion of evaluation the prognosis of critically ill patients. Promoting the recovery of gastrointestinal motility function could effectively prevent MODS from deteriorating to multiple organ failure (MOF). Interstitial cells of Cajal (ICC) as a pacemaker cell in gastrointestinal tract, can spontaneously generate slow wave which determine the rhythm of gastrointestinal smooth muscle contraction and is the basis for gastrointestinal motility. The connection of ICC and ICC, ICC and smooth muscle cell (SMC), SMC and SMC are through gap junctions. The connection between the nerve terminals and intramuscular ICC (ICC-IM) via synaptic-like connection. The network of enteric nerve-ICC-smooth muscle is the basic unit of gastrointestinal motility. Enteric nervous neurotransmitter is chiefly passed to the ICCs. ICCs transmit the signal of after integration to the muscies through gap junction intercellular communication(GJIC)mediated by GJ, thereby gastrointestinal motility is regulated. Connexin (Cx) is the basic structure and proteins of function formed GJ. Cx43 is the most widely distributed Cx in the Cxs family and is the most important Cx constituted GJ. The normal expression and distribution of Cx43 is the basis for enteric nerve-ICC-SMC network playing gastrointestinal motility function. GJ formed by Cx43 is transfer station for information integration, mediate exchange of electrochemical information between the ICCs and SMCs, and ensure the coordination and synchronization of muscle activity, resulting in the occurrence and regulation of gastrointestinal motility. Abnormalities expression and distribution of Cx43, decreasing of the quantity of GJ and structural damage of GJ often lead to gastrointestinal motility disorders.Objective To observe the distribution of connexin 43 and the quantity and structure changes of gap junction formed by Cx43 in intestinal muscle of rats with MODS, and the effect of Dachengqi Decoction(DCQD) on Cx43 and GJ in intestinal muscle with MODS, to explore the mechanism of gastrointestinal motility disorders leaded by MODS, and to investigate the theory of effect of DCQD on MODS.Methods One handred Wistar rats of both sexes weighing about 250g were randomly divided into three groups:control group(n=20), MODS group(n=40)and MODS+DCQD treated group(n=40). The model of MODS was established according to previous study. Briefly, 1ml suspension of 8 X 108cfu/ml of Escherichia coli strain 0127 H6, which contained 10%BaSO4, was injected under sterile conditions into the peritoneal cavity of the rats in the MODS and MODS+DCQD treated group. The rats of control group were injected lml of normal saline. The rats of DCQD treated group were administrated by gavage with DCQD(twice a day) before the suspension was injected. Twenty-four hours after injection, the proximal small intestine was taken.After some of the small intestine for formaldehyde fixation, paraffin embedding, immunohistochemistry (ABC method) staining Cx43, and then coverslipping, the expression and distribution Of Cx43 in the intestinal muscle were observed, The Images were collected for statistical analysis.Other intestinal was put in cold 2.5%glutaraldehyde fixative, the tissue was cut into 2mm×5mm pieces, fixed, dehydrated, impregnated, embeded, semi-thin section was prepared, located on the light microscope, the thin slice was prepared. The quantity and structural changes of GJ in network of enteric nerve-ICC-SMC were observed, the images were collectted for statistical analysis.Results Anatomical changes The gastrointestinal tracts were extremely dilated in the rats with MODS compared with in control group; Compared with the MODS group, the dilated gastrointestinal tracts was markedly alleviated in MODS+DCQD treated group.Immunohistochemistry study The characteristic of Cx43 immuno-reactivity in control group was brown sediment, it was densely distributed throughout the whole circular muscle layer in an almost homogeneous fashion, particularly around the outer edge of the circular muscle layer and the inner surface adjoining the mucosa, mainly located in the cell membrane and cytoplasm. In the longitudinal muscle layer the immune expression was weakly. In MODS group, the brown sediment was less than the control group (p<0.01). The immunostaining of Cx43 located sparsely in the circular muscle, in particular around the outer edge of the circular muscle layer and the inner surface adjoining the mucosa. In the MODS+DCQD treated group the brown sediment was more than in the MODS group (p< 0.01), which distributed densely, mainly located the circular muscle, in particular in outer edge of the circular muscle layer and the inner surface adjoining the mucosa, while the longitudinal muscle layer with very weak immune reaction or immune reaction disappeared. There was not obvious different between DCQD treatment group and control group.TEM observation In control group, there were gap junctions between ICC-DMP and ICC-DMP, ICC-DMP and SMC and between SMC and SMC. The gap junctions were plate-like connection, commonly in deep side of the surface of the cells, the gap junction between adjacent cell membranes was only separated by 2 nm. There were a number of cylindrical combination, combination across the both sides plasma membrane to form gap junctions. The cells in the network of enteric nerve-ICC-smooth muscle connectted each other closely and the network structure remained intact.In MODS group, the gap junctions between ICC-DMPs, ICC-DMPs and smooth muscle cells and between smooth muscle cells was not found, there were widened gaps between cells. There was significantly expanded perinuclear space in ICC, nuclear chromatin condensation and margination. Mitochondria was decreasing and swelling, and cell membrane structure was fuzzy. The connection between the cells in the network of enteric nerve-ICC-smooth muscle was disappeared.In MODS+DCQD treated group, there existed gap junctions among ICC-DMPs, between ICC-DMP and SMC and among SMCs. The gap junction between adjacent cell membranes was only separated by 2 nm, There was cylindrical combination in the gap. The cells in network of enteric nerve-ICC-smooth muscle connectted each other closely and network structure remained intact. There were distinct cytomembrane and prominent nucleoli, no chromatin margination phenomenon in ICC. There were more mitochondria in the cytoplasm, and some of them was swelling. The cells in network of enteric nerve-ICC-smooth muscle connectted each other closely and network structure remained intact.Conclusion There was extreme expansion of gastrointestinal and obvious signs of intestinal obstruction in MODS rat induced by bacterial peritonitis; DCQD can significantly alleviate the signs of paralytic intestinal obstruction.The expression and distribution of Cx43 were reduced greatly in rat with MODS, and DCQD could protect the structure damage of Cx43 in MODS rat.The quantity of GJ in network of enteric nerve-ICC-smooth muscle declined in in rats with MODS, and the structure was damaged. DCQD can maintain the quantity of GJ, protect structure of GJ from destructing, thereby maintained the structural and functional integrity in gastrointestinal network of enteric nerve-ICC-smooth muscle.
|
PDF Full Text Request