Changes Of Gastric Mucosa Injury With Aging In Rats

Objective:1.Observing gastric mucosa changes and pepsin activity with aging in rats.2.After intragastric administration of asprin and omeprazole,observing the pathological changes of gastric mucosa and the difference of serous NO and TNF contents,then investigate the influence and mechanism of impaired and protective factors on aged and non-aged rats.Methods:18 healthy wistar rats of 3-month and 22-month were respectively and randomly divided into 3 groups:normal control group,aspim group and omeprazole group.1.Aspim group and omeprazole group were intragastric administered by aspin and omeprazole respectively.Normal saline was intragastric administrated to control group.NO contents,NOS and iNOS activity were detected by NO kit and NOS kit,TNF contents was detected by radioimmunity.Compared the degree of gastric mucosa injury according to the Guth score standard and Whittle score standard under light microscope.2.Observing the height of gastric mucosa gland and the height of muscularis mucosae under light microscope between aged rats and non-aged rats,pepsin activity was detected by chemic method,the expression of PCNA was detected by immunohistochemistry methods and gastric juice was collected to detect PH.Results:1.Non-aged rats of normal control group were active with burnish and white fur,while the aged rats of normal control group were inactive with yellowish and rough fur.Gastric mucosa of the former group were smooth and gloosy,red in color and covered with much mucosa fluid,gastric mucosa of the latter group were pale in color and also covered with much mucosa fluid.Intestinal metaplasia dysplasia and adenoma were not found in aged and non-aged gastric mucosa.The aged mucosa gland of antrum decreased in number with a concomitant expansion of the interglandular connective tissue,the height of aged muscularis mucosa thicken and inserted into the substantia propria like branchs,but there were no much of lymphocyte infiltrated in both normal control group.The PH of gastric fluid in aged normal control group was higher than that in non-aged rats(P＞0.05),the contents of pepsin in aged gastric mucosa were lower(P＜0.05), immunohistochemistry results showed:PCNA normally expressed in non-aged normal control group,the positive cells located in stem cells of the neck region,the positive cell nucleus stained yellowish-brown,superficial epithelial cells expressed negative,the location of positive bands approached to muscularis mucosa and the height of positive stained stem cells were lower than that of non-aged rats.the contents of NO,TNF and the activity of NOS iNOS increased,with the activity of cNOS decreased.All of these illustrated the contents of NO generated by cNOS decreased and the contents of NO generated by iNOS increased,all of these could be induced by the damage of free radical.2.Bleeding points and erosion could been seen on the gastric mucosa of aged and non-aged aspim-injured groups and the damage of aged injury group was serious than the non-aged injury goups(P＜0.05).Under microscope we could see there were hyperemia,hydropsia,epithelial damage and mild inflammatory infiltration,th whittle scores of the aged injured group were higher than that of the non-aged injured group(P＜0.05).After intragastric administration of omeprazole,the damage of protective groups lessened compare with the injury groups,the manifestation was erosive and hemorrhagic degree was more mild than the injury groups according to the Guth score standard and Whittle score standard.Analysis of variance showed:compared with the normal control groups,the contents of TNF and NO,the activity of NOS and iNOS increased, the activity of cNOS decreased in both injury groups and had statistical changes with control group.The contents of NO decreased in both protective groups than that in injury groups and increased in normal control groups(P＜0.05).The activity of NOS in aged and non-aged protective groups decreased compared with both injury groups and increased compared with control groups(P＞0.05).The activity of iNOS in non-aged protective group decreased compared with injury group and increased compared with control group(P＜0.01).The activity ofiNOS in aged protective group decreased compared with injury group(P＜0.01)and had no statistical changes compared with control group.The activity of cNOS in both protective group decreased compared with injury group(P＜0.05)and had no statistical changes compared with control group.The contents of TNF in both protective group decreased compared with injury group(P＜0.05)and had no statistical changes compared with control group.The activity of iNOS,the contents of NO and TNF were relevance to lesion,the indecorrelation coefficient was 0.6871,0.7338,0.7824 respectively,correlation coefficient of cNOS with lesion index was -0.7458,the activity of NOS has no relevance with lesion index.Condusion:1.The incidence of atrophic mucosa gland and thickened muscularis mucosa increased in aged rats.The secretion of gastric pepsin antigen decreased.The proliferation of gastric stem cells in the neck region decreased.2.Gastric mucosa was more sensitive to injury factors and gastric mucosa repair ability decreased in aged rat.3.The damage mechanism of aspirin maybe revalance with the increased iNOS activity,the increased NO and TNF contents,the decreased cNOS activity.Omeprazole protected injury mucosa maybe by the mechanism of decreased the contents of TNF and NO.