| 【Objective】To establish nonalcoholic fatty liver disease(NAFLD) model by high fat diet in rats, to observe the relationship between NAFLD and small intestinal mucosal barrier lesion, to observe the therapeutic effect of teduglutide on NAFLD rats, then investigate the potential role of small intestinal mucosal membrane in the pathogenesis of NAFLD.【Materials and methods】Chapter 1:Forty-eight male SD rats were randomly divided into the normal diet group(CD group, n =24) and high fat diet(HFD group, n = 24), with free access to food in each group. During the experiment, the general state of the rats was observed daily, including diet and hair changes and so on. Recorded food and water intake as well as the weight of the rats in every other day. When feeding to the 6th, 8th, 10 th, 12 th weeks, six rats were randomly selected respectively from the two groups and implemented with regional anesthesia by diethyl ether. Then blood samples were collected from the ocular veniplex and rats were sacrificed to collect the liver, duodenum and jejunum samples for further correlative detection including Hematoxylin-Eosin(HE) and Immuno-histo-chemical(IHC)staining and so on.Chapter 2:Fifty-four male SD rats were randomly divided into the normal diet group(ND group, n =18), NAFLD group(n = 18) and GLP-2 group(n = 18), with free access to food in each group. When feeding to the 8th, 10 th, 12 th weeks, six rats were randomly selected respectively from those groups. Rats in the GLP-2 group were given teduglutide(250 μg/kg,namely 0.1 m L/100 g)by intraperitoneal injection twice daily and the other two groupswere injected with an equal volume of saline for 7 days. Then rats were given local anesthesia and blood samples were collected from the ocular veniplex. Once sacrificed, the rats were dissected to collect the liver, duodenum and jejunum samples for further correlative detection.【Result】Chapter 1:(1) The weight of the rats in the HFD group was higher than the CD group in the same term and since the 4th week the difference appeared significant. Rats’ serum lipid levels such as TC, TG and LDLC in the HFD group increased gradually and were higher than those of the CD group in the same term; the difference gradually appeared statistically significance.There was no significant difference of the HDLC level between the two groups. Rats’ TC and TG levels of the liver homogenate in the HFD group were higher than those of CD group in the same term(P<0.05), so did the levels of serum ALT and AST in the two groups.(2) The NAFLD activity score(NAS) in the HFD group was significantly higher than that of the CD group since the 6th week(P<0.01).(3) Duodenal/jejunum HE staining since the8 th week in the HFD group showed that cell arrangement became loose and the gap between cells increased. The IHC scores of the duodenum/jejunum mucosal epithelial protein ZO-1in the HFD group were lower than those of the CD group since the 10 th week(P<0.01),while the IHC scores of Claudin-2 in the HFD group were higher than those of the CD group since the 10 th week(P<0.01).Chapter 2:The weight of the rats in those groups displayed an increasing trend, the rats’ weight of the NAFLD and GLP-2 group were higher than that in the ND group, and there was a significant difference in the 13 th week(P<0.05). Rats’ serum TC and TG levels of GLP-2group were slightly higher than those of the ND group and it didn’t show significant difference until the 13 th week(P<0.05). Rats’ serum LDLC levels of GLP-2 group were slightly higher than those of the ND group and it showed significant difference only in the9 th week(P<0.05). There was no significant difference of serum HDLC level among those groups. Rats’ TC and TG levels of the liver homogenate in the GLP-2 group were lowerthan those of the NAFLD group(P<0.05) but still higher than the ND group(P<0.05) in the same term, so did the levels of serum ALT and AST.(2) The NAS in the GLP-2 group was significantly lower than that of the NAFLD group(P<0.01) but still higher than that of the ND group(P<0.05) since the 9th week.(3) Duodenal/jejunum HE staining in the NAFLD group showed obvious loose of cell arrangement and increase of cellar interval, while no clear change had been found in the ND and GLP-2 groups. The IHC scores of the duodenum/jejunum mucosal epithelial protein ZO-1 in the GLP-2 group were higher than those of the NAFLD group(P<0.01) but were lower than those of the ND group(P<0.05).The IHC scores of the duodenum/jejunum mucosal epithelial protein Claudin-2 in the GLP-2 group were significantly lower than those of the NAFLD group(P<0.01) while slightly higher than those of the ND group.【Conclusion】The incidence of NAFLD can lead to the enlargement of the intercellular space of intestinal mucosa, decrease of ZO-1 protein expression and increase of Claudin-2 protein expression.Teduglutide might improve the liver lesions in NAFLD rats by regulating the expression of the ZO-1 and Claudin-2 protein in the intestine. |
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