The Change And Significance Of EPCs In Rat Model Of Portal Hypertension With Esophageal Varices

Objectives: To establish a portal hypertension animal model by partial portal-vein ligationin rats, isolate and identify the EPCs from peripheral blood and analyze the counts ofEPCs in the portal veins between the two groups.Methods: Sprague-Dawley male rats were randomly divided into two groups: the modelgroup (by partial portal-vein ligation plus left adrenal-vein ligation); the control group(sham operation). The rats were killed at the2nd and4th weeks and the portal pressurewas measured, the liver, esophageal and gastric tissue were frozen in liquid nitrogen andembedded in paraffin. Isolate the mononuclear cells by Ficoll solution from portal blood(PBMC). The cells were identified using immunocytochemical methods and their numberswere counted.Results: The portal press of rats in model group was significantly higher than that of thecontrol group and sham operation group. There are visible esophageal and gastric varices.After2~3weeks the primary cells formed colonies, and the cells express the EPC surfacemarker CD133and VEGFR-2. There were significantly more EPC colonies in theexperimental group than in the control group.Conclusions: Using the method of partial portal-vein ligation, we could establish a portalhypertension model with esophageal varices. The level of EPCs has a relationship withportal hypertensive vasculopathy. Objective: To evaluate the role of EPCs in the portal hypertension with varices.Methods: Rats in each group were sacrificed at different time points, theparaffin-embedded esophageal tissue sections were stained with hematoxylin and eosin(H&E). The images were acquired using a Nikon Digital ECLIPSE C1system (Nikon,Tokyo, Japan) and were analyzed using Image-Pro Plus6.0software by pathologists. Thenumber and area of the esophageal submucosal veins were counted. The expressions ofCD133and VEGF in esophageal tissue were detected by immunohistochemical method.Levels of VEGF in the sera and esophageal tissue were detected using a commercialELISA kit, following the manufacturer instructions.Results:(1)The densities of the esophageal submucosal veins were significantly increasedin the rats with esophagogastric varices, and the EPC colonies were significantlycorrelated with the density of the esophageal submucosal vein and the percentage ofsubmucosa occupied by the veins.(2)CD133and KDR-positive endothelial cells could bevisible in esophageal submucosal blood vessels of rats in model group, and the cells werenot found in rats in the control group.(3)The level of VEGF in tissues homogenate wasnot statistically significant among each group. The level of VEGF in model group wassignificantly increased at the4th week after operation.Conclusions: CD133and KDR-positive endothelial progenitor cells may be involved inthe formation of varicose veins in the rat model of portal hypertension. Raised levels ofVEGF in serum may promote the participation of EPC in the formation of the esophagealvarices.