The First Part Is To Study The Protective Mechanism Of Ghrelin On Acetic Acid-induced Gastric Injury In Rats. The Second Part Is To Evaluate The Pharmacodynamics Of Gastroprotective Drugs

To explore the protective effect and mechanism of ghrelin on acetic acid-induced chronic gastric injury in rats.Method:Gastric ulcer was induced by micro-injection of acetic acid under gastric mucosa membrane in Wistar rats.Rats were sacrificed and stomachs were taken out on the 3rd,6th,and 9th day after the operation,and the area of the ulcer were evaluated.Immunohistochemistry was used to detect PCNA-positive cells in the gastric tissue around gastric ulcer.Concentration of acylated,unacylated ghrelin and IL-1 ? in serum,IL-1 ?,TNF-? and VEGF levels in gastric tissue around ulcer were measured by ELISA,expressions of iNOS and eNOS in lesion area around gastric ulcer were measured by western blot.The results showed that induction of gastric ulcer significantly reduced ghrelin level in serum.Result:Ghrelin(30 ?g/kg,ip,bid)could promote the formation of new basal tissue in gastric ulcer on the 3rd day and significantly reduced the wound area of gastric ulcer(40%and 80%respectively)on the 6th and 9th day after induction of gastric ulcer,meanwhile prominently increased the number of PCNA positive cells in gastric tissue around ulcer.Ghrelin could remarkably inhibit the expression of IL-1? in serum(P<0.001)and significantly reduced the contents of IL-1?(P<0.001)and TNF-? in gastric tissue around ulcer.Compared with the Model group at the same time,ghrelin inhibited the activity of iNOS in serum after 6 days of administration,and reduced the expression of iNOS protein in gastric tissue around ulcer during the whole experiment period(P<0.01).In addition,ghrelin also increased the expression of eNOS protein in gastric tissue around ulcer after 6 consecutive days of administration(P<0.001),and significantly increased the expression of VEGF in gastric tissue around ulcer during the whole experiment period.Cell experiment results showed that ghrelin(10-8 M)has a good protective effect on LPS-induced apoptosis of gastric parietal cells,can significantly reduce the content of IL-1 ? and TNF-? in the culture medium,and increase the content of VEGF.and this protective effect can be blocked by VEGFR antagonists to a certain extent.Conclusion:Animal experiment results show that ghrelin(30 ?g/kg,ip,bid)had a significant protective effect on acetic acid-induced gastric injury in rats.Cell level experiments show that ghrelin has a good protective effect on LPS-induced gastric parietal cell apoptosis,and this protection effect can be antagonized by VEGFR antagonists.Ghrelin(10-8M)can inhibit the synthesis and release of TNF-? in the injured part of the stomach to a certain extent,thereby inhibiting the expression of IL-1?,which in return inhibiting the synthesis of NF-?B in macrophages,monocytes and smooth muscle cells,and inhibiting the overexpression of iNOS inflammatory pathway thus indirectly promotes platelet adhesion and wound healing.At the same time,ghrelin can also promote the expression of VEGF in the early gastric ulcer tissue of the injury,promoting the expression of eNOS protein,thereby activating the VEGF-eNOS-SP1 pathway and accelerating the angiogenesis of the surrounding tissues of in the stage of early gastric ulcer injury,then promoting the repair of the gastric ulcer tissue.In this study,in vivo and in vitro experiments were conducted to evaluate the gastroprotective effect of 3 batches of Jacaranda extract and Ilaprazole(ILP),L-ILP(laveo-Ilaprazole,L-ILP)and dextro-Ilaprazole(dextro-Ilaprazole,D-ILP),which provides a certain basis for process production.Methods:Ethanol gavage(3.5 g/kg)and acetic acid-induced rat gastric injury model were used to evaluate the gastroprotective effect of 3 batches of Jacaranda extract.The morphology of gastric mucosa was observed by tissue sections.The expression of PGE2 in gastric and glandular stomach was determined by ELISA.Vitro experiments were conducted to evaluate the inhibitory activity of ILP,L-ILP,and D-ILP on H+-K+-ATPase.At the same time,the rat gastric injury model was induced by water immersion restraint and pyloric ligation to evaluate ILP,L-ILP,D-ILP gastric Protective effects.Results:All of the 3 batches of Jacaranda extract(GXYSP-J20-SZ-95%,30 mg/kg,ig)had a significant protective effect on ethanol-induced gastric injury in rats,and the inhibition rate of gastric ulcer was close to 100%.The protective mechanism of alcohol-induced gastric injury in rats may be related to its inhibitory effect on the synthesis and release of PGE2 in the proventriculus tissue.At the same time,3 batches of Jacaranda,extracts(10 mg/kg,ig,11d)administered consecutively for 11 days had a significant protective effect on rats with gastric injury induced by acetic acid.The results of in vitro experiments show that ILP,L-ILP and D-ILP(10-5,10-6 M)had inhibitory effects on H+-K+-ATPase activity,but there is no significant difference in inhibition rate.IL-P,L-ILP and D-ILP(5 mg/kg,ig)had a good protective effect on rat gastric injury induced by water immersion restraint,and the efficacy of ILP is slightly stronger than that of L-ILP.D-ILP has relatively the worst effect.