Establishment of Helicobacter pylori infection model in Mongolian gerbils

AIM:To establish a stable and reliable model of Helicobacterpylori infection model in Mongolian gerbils and to observepathological changes in gastric mucosa in infected animals.METHODS:Mongolian gerbils were randomly divided into18 groups;6 groups were infected with Hpyloriclinical strainY06 (n=6,groups Y),6 groups were infected with Hpyloristrain NCTC11637 (n=6,groups N),and 6 uninfected groupsas negative controls (n=4,groups C).Hpylorisuspensionsat the concentrations of 2×10~8 and 2×10~9 CFU/mL of strainNCTC11637 and strain Y06 were prepared.The animals inthree groups N and in three groups Y were orally challengedonce with 0.5 mL of the low concentration of the bacterialsuspension.The animals in another three groups N and inanother three groups Y were orally challenged with 0.5 mlof the high concentration of the bacterial suspension for 3times at the intervals of 24 h,respectively.For the negativecontrols,the animals in six groups C were orally givenwith the same volume of Brucella broth at thecorresponding inoculating time.The animals were killedafter 2nd,4thand 6thweek after the last challenge andthe gastric mucosal specimens were taken for urease test,bacterial isolation,pathological and immunohistochemicalexaminations.RESULTS:Positive isolation rates of Hpyloriin the animalsof groups Y at the 2nd,4thand 6thweek after one challengewere 0%,16.7% and 66.7%,while in the animals of groupsN were 0%,0% and 16.7%,respectively.Positive isolationrates of Hpyloriin the animals of groups Y at the 2nd,4thand 6thweek after three challenges were 66.7%,100%and 100%,while in the animals of groups N were 66.7%,66.7% and 100%,respectively.In animals with positiveisolation of Hpylori,the bacterium was found to colonizedon the surface of gastric mucosal cells and in the gastricpits,and the gastric mucosal lamina propria was infiltratedwith inflammatory cells.CONCLUSION:By using H pylori suspension at highconcentration of 2×10~9 CFU/mL for multiple times,the orallychallenged Mongolian gerbils can be used as a stable andreliable H pylori infection model.The 2 strains of H pylorican colonize in gastric mucosa of the infected animals and cause mild inflammation reaction.