Abstract:Aim\ A comparison of the macroscopical and histological appearance in granulomas was made induced by Mycobacterium Paratuberculosis(MP) and Crohn's Disease(CD) tissue in hamsters,in order to investigate whether MP plays an etiologic role in CD.Methods\ 40 hamsters were inoculated intraperitoneally,twenty received MP,ten received dead inoculum and ten received saline.Each CD homogenated was prepared immmediately after biopsy,100μl homogenates was analysed by PCR;and 40μl was inoculated intramurally into the cecum and terminal ileam of each hamster of 5,tissue was obtained from intestine and evaluated macroscopically nad histologically.Each hamster inoculated intramurally was scored on the criteria for assessment of intestine damage.Results\ Microscopically,16 of 20 hamsters received MP showed granulomatous changes,the control hamsters didn't show granulomatous enteritis.Two of five CD homogenates were positive for MP.The hamsters received PCR positive CD homogenates put on granulomatous changes involved in 5 of 10.The correct 400bp amplification product was obtained again in the granulomatous intestinal tissue of 5 hamsters inoculated PCR positive CD homogenates when the IS900 PCR was applied.Only 1 of 15 hamsters received PCR nagative CD homogenates showed granulomatous change.The average score of hamsters intestinal damage induced by PCR negative CD homogenates was 3 66±1 71 and showed a marked increase(P<0 05) as compared with those of normal gut mucosa group;but no statisically significant difference(P>0 05) was shown when compared with PCR positive CD homogenates group.Conclustion\ MP may play an etiologic role in at least some cases of Crohn's disease.Other factor may also play an etiologic role in some cases of CD except MP.
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