The Effects On The Liver Tissue Structure And Apo-E Expression By Thoracic Duct Ligation On The Obese Rat

Objective: The liver is the body's vital organs, in the material metabolism,fat metabolism and the biotransformation plays an important role.Apolipoprotein E (apolipoprotein E, Apo-E) is the Shore in1973, first foundin the normal very low density lipoprotein synthesis by the liver cells,chylomicrons (CM), very low densitylipoprotein (VLDL) and high densitylipoprotein (HDL) component of very low density lipoprotein receptor ligand;it also transformation and metabolic processes involved in the lipoproteins,the genes can regulate many biological functions. As we all know, thelymphatic channels is a one-way drainage pipe from various organs, tissuesrecovery of lymph, fat and protein macromolecules, and then injected into theblood in the form of lymph. The liver to produce a large number of lymphnodes, mostly from thoracic duct reflux. Understanding of the Apo-E, haveimportant physiological and pathological significance to transformation andmetabolism of lipoproteins. In this study, to be adopted by the SD rats on anormal diet and high fat diet fed SD rats, the ligation of the thoracic duct, ananimal model of liver tissue, the Apo-E immune response in contrastobservation of the positive cell morphology, to explore the Apo-E transporter,as well ashigh fat diet, experimental lymphatic stasis, affect the morphologyof the liver tissue, respectively, to provide morphological evidence.Methods:1Experimental animals and derivedSelection of40one-month-old healthy SD rats, weighing about100g,male or female, is about12cm (nose to base of tail), provided by theExperimental Animal Center of Hebei Medical University. They wererandomly divided into two groups: group A, normal diet group (20); group B,high-fat diet group (20).10weeks after the feeding, the group A were randomly divided into group A1, the sham group (10); A2, group, operationgroup (10); group B were randomly divided into the B1group, sham group(10); B2,group, surgery group (10). After the success of the modeling werefed six subjects, the liver tissue for light and electron microscopy.2Sample preparation and observation of the light microscopeParaffin-embedded liver tissue sections, OK HE staining and observed bylight microscopy; to show the fine structure of the liver, the distributioncharacteristics of the vascular system.3Immunohistochemical staining and observed by light microscopyGroup A and group B SD rat liver tissue paraffin sections, line the Apo-E,immunohistochemical staining, light microscopy results of the Apo-E and itsreceptor immunohistochemistry, the immune response in various types of cellsin the liver tissue positiveexpression.4Scanning and transmission electron microscopy (TEM) sample preparationand observationThe liver specimens were conventional scanning and transmissionelectron microscopy (TEM) sample preparation and observation; to reveal theultrastructural features of the SD rat liver tissue, as well as experimentalhigh-fat feeding and lymphatic stasis, respectively, the impact on the livertissue and cell ultrastructure.Results:1Naked eye in experimental surgeryBecause the preoperative administration of animal poured cooking oil,absorption through the gut, the mesenteric lymph duct, and intestinal stemcisterna chyli and thoracic duct, milky white due to the absorption andtransport of chylous material, intraoperative easily recognizable. Accurately atthe foot of the abdominal diaphragm after ligation of the thoracic duct ligationsite was lymphatic filling thicker.Experiment visible to the naked eye, the A1group of liver, dark red, andshiny, smooth capsule, the edges are rounded; group A2, B1group and B2group of liver volume increases, the blunt edge of the capsule tension, surface dull, greasy feeling.even visible adipose tissue wrapped.2HE staining tissue sections observed by light microscopyIn the sham operation group (A1), the liver tissue structural integrity and aclear structure of hepatic lobule, the center of the hexagonal hepatic lobule,showing a central vein; liver cell cord central venous arranged radially around.In the portal area between the adjacent liver lobule, we can see three pipes:interlobular artery interlobular vein, interlobular bile duct accompaniedexistence. Liver tissue in the surgery group (A2), the increase in the numberof fat cells, the volume occupied by large, diffuse fatty degeneration;hepatocyte swelling increases around the hepatic sinusoid space narrowing;the portal area inflammatory cells infiltration, mainly lymphocytes.Be seen in the sham operation group (B1), liver tissue infiltration of fatcells; different sizes of spherical vacuoles in the part of the liver cellcytoplasm, cytoplasmic matrix loose, showing the limitations of steatosis.Liver cell membrane tension, the color fades. Vacuolated fat cell numberincreased in the surgery group (B2), liver tissue, the larger size; liver cellsswell and round nuclei pushed to the cell side; a small amount of hepatocytenuclear pyknosis or necrosis phenomenon. hepatic lobule showing necrosis;portal area connective tissue infiltration of inflammatory cells, mainlylymphocytes. In the liver tissue, severe fatty degeneration; then liver tissuestructure becomes incomplete, abnormal structure of the hepatic lobule, andeven showing focal necrosis.3Immunohistochemical staining observed by light microscopyIn the sham operation group (A1), the liver tissue visible uniformapolipoprotein E immunoreactive results, showing a brown particulate matterdeposition. In the surgery group (A2), the liver tissue of the positive results ofthe visible enhance the immune response of apolipoprotein E, tan increasedparticle deposition, and statistically significant.In the sham operation group (B1), liver tissue visible, similar to the shamoperation group (A1), uniform apolipoprotein E immunoreactive results,showing a brown particulate matter deposition. Surgery group (B2) can be seen apolipoprotein E immune response similar to the surgery group (A2)positive expression of enhanced brown particulate matter deposition increase,and statistically significant.4Transmission electron microscopy of thin tissue sectionsIn the sham operation group (A1), the liver cell membrane structure isclear, the nucleus round and centered, multiple nucleoli visible in the corecentral area; the cytoplasm of liver cells, showing that a large number ofmitochondria, rough endoplasmic reticulum, and plasminbodies and otherorganelles. No inflammatory cell infiltration and fibrous hyperplasia. In thesurgery group (A2), thickening of the nuclear membrane of the hepatocytenuclear, nuclear chromatin aggregation, cytoplasmic open, lower electrondensity, and fatty degeneration of the performance. Between Disse of the liversinusoids and within the liver cells, showing that the deposition of lipids,fibrous connective tissue increased. Easy to see that to reduce the size of livercell organelles in the cytoplasm; nucleus pyknosis, shrinkage, electron densityis significantly enhanced.In the sham operation group (B1), hepatocyte nuclear chromatin gathered,the matrix uneven distribution of organelles in the cytoplasm of reducedmatrix increased, the apparent lipid deposition. Deposition of lipid materialcan be seen between the liver cells and increase of connective tissue fibers. Inthe surgery group (B2), hepatocyte nuclear membrane is not continuousincrease of the nuclear pore. Between Disse of the liver sinusoids and withinthe liver cells, showing that a large number of lipid deposition, fibrousconnective tissue was significantly increased. Easy to see the nucleuspyknosis, apoptosis, liver cell cord derangement, capillary bile duct dilatationand cholestasis. In some cells, showing large mitochondria. Roughendoplasmic reticulum, part of degranulation, cytoplasm lipid droplets.Between hepatocytes and periportal areas, but also shows the proliferation ofconnective tissue fibers.5Scanning electron microscopeScanning electron microscopic observation showed, in normal rat liver surface, covered with a layer of flattened epithelial cells formed byperitoneum; in the flat surface epithelial cells, especially in epithelial cells ofthe edge of the site, the existence of a large number of plate and the fingermicrovilli, epithelial cells contained prominent nuclear site, uplift. In theobese or ligation of thoracic duct in rat, the liver is the membrane surfaceepithelium microvilli obviously reduced.Conclusion:1Thoracic duct lymph drainage for liver main channel; in the abdomendiaphragm at the foot of the ligation of the thoracic duct, hepatic lymph stasiscan successfully establish experimental animal model.2Long term high fat diet induced obese rats induced liver tissue, lipiddeposition, affecting lipid metabolism, and even cause damage of liverfunction.3Experimental hepatic lymph stasis can affect lipid transport and metabolism,induced liver fat accumulation in the liver cells, fatty degeneration, Apo-Eimmunoreactivity expression is enhanced; hypothesized that thoracic duct isthe important way to transfer Apo-E.