The Animal Experimental Study Of Reflux Esophagitis Induced By Exogenous Factors In SD Rats

Objective:The purpose of this study was to establish the Animal models of reflux esophagitis(RE), to observe the general morphous and pathological change of models'esophagus, and study the expression of cycloo-xygenase-2 in esophageal tissues of SD rats with reflux esophagitis. And some experiment and theory foundation were provided to reflux esophagitis.Methods:40 SD male rats (weighing 220-240g) were randomly divided into test group and control group:(1) The experimental group (n=30) received mixed alcohol/tallow solution (3:2) by gavage at 14:00 every day, from 10mL/kg to 15mL/kg increasing 2.5mL/kg every 3 day, for 12 week. High fat emulsion formula:pork fat 500g, cholesterol 100g, cholic acid 33g, propylene glycol 150mL as well as distilled water 200mL were mixed to homogeneous emulsion. Preparation of mixed alcohol/tallow solution:56°liquor was mixed with above high fat emulsion formula (3:2 v/v) to form cream-colored milkly solution.The normal control group (n=10) were given equal volume of saline. The test group rats and control group rats were fed with common granulated feed and drinking water randomly, and kept in captivity in clean grade animal laboratory with room temperature of (23±2)℃and moisture of (55±5)%.(2) Ten rats were killed respectively in test group at the 4th,8th and 16th week, by fasting 24 hours and fasting in liquid 6 hours. About 3cm esophagus was opened longitudinally from the superior edge of esophagus cardiac, and selected the middle-lower section to observed the general morphous and pathological changes of esophagus, and study the expression of cyclooxygenase-2 in esophageal tissues of SD rats with reflux esophagitis. The SD rats in control group were killed at 12th week, and treated as the same above.(3) Using statistic software SPSS 16.0 to deal with data.Results:(1) Survival rates:The survival rates of 4th,8th and 12thweek were 100%, 90% and 100% respectively in test group, and 100% in control group.(2) Esophageal mucosa classification by eyes:test group (4th week)Ⅰgrade 60%,Ⅱgrade 40%; (8thweek)Ⅰgrade 50%, II grade 30%,Ⅲgrade 20%; (12thweek)Ⅱgrade 50%,Ⅲgrade 50%. And all of that in control group is 0 grade.There were significant differences in the esophageal mucosa classification by eyes between test group and control group.There were significant differences between test group(4th week) and test group(8th week) (X2=11.075, P<0.05)(3) HE staining pathologic grading:Test group (4thweek) mild 60%, moderate 40%; test group (8thweek) mild 50%, moderate 30%, severe 20%; test group (12thweek) moderate 50%, severe 50%. The mucous membranes of esophagus was normal on control group, with membrane being infiltrated by a little of lymphocytes occasionally. Significant difference was existed in the HE staining pathologic grading between test group and control group. Significant difference was existed between test group(4th week) and test group(8thweek) (X2=11.075, P<0.05)(4)Expressions of cyclooxy-genase-2(COX-2):There were significant difference in the expressions in different stages (4th,8th and 12th week), expressed strongest in 12th week and weakest in 4th week.Conclusions:(1) In the preparation of animal model of reflux esophagitis in SD rats, there were significant differences in test group (4th,8th and 12th week) contrasted to control group, which showed that establishment of animal model has a certain scientific practicality and feasibility.(2) The observe to survival rates and longevity, indicated that the animal model established in this paper can be kept for feed and have long survival time, also provided a reliable experimental animal model for the study of reflux esophagitis.(3) sophageal mucosa classification by eyes, pathologic observation grading and expressions of cyclooxy-genase-2(COX-2) in different periods of test group was a continuous damage process, and as time goes on, the damage was increasing.