A Preliminary Study On The Protective Effects Of Aplysin On Intestinal Mucosal Damage Of Rats Exposed By Excessive Iron

Objective:To observe the effects of aplysin on iron metabolism,intestinal barrier and intestinal flora,and to explore the protective effect mechanism of it on intestinal mucosa in rats exposed by excessive iron.Method:1.Animal model establishing and grouping:Forty-eight male Wistar rats were randomly divided into four groups:control group,received basic diet;model group,received diet containing Fe²⁺1 000 mg/kg;Aplysin group,administered daily Aplysin dose of 150mg·(kg^-1·bw^-1·d^-1);Aplysin+iron group,received diet containing Fe²⁺1 000 mg/kg and administered daily Aplysin dose of 150 mg·(kg^-1·bw^-1·d^-1),and 5 mL/?kg.d?soybean oil was administered to the control and model groups by gavage,respectively.The experiment lasted for twelve weeks.After the last gavage,feces were collected from rats in each group with metabolic cage.After fasting for 12 hours,3%pentobarbital sodium was anesthetized intraperitoneally,blood was taken from abdominal aorta,and small intestinal HE and electron microscope specimens were taken.The remaining tissue was frozen quickly and then transferred to-80?refrigerator for storage.2.Iron metabolism index detection:The levels of liver iron and serum iron were measured with inductively coupled plasma-mass spectrom etry?ICP-MS?.Serum ferritin?SF?and serum iron hepcidin?HEPC?levels were detected by ELISA method.And Western Blot detection were utilized to detect DMT1?divalent metal iron transporter protein?and FPN1?membrane iron transporter?in small intestine.3.Intestinal barrier function testing:The histopathology of small intestine was observed after hematoxylin-eosin?HE?staining.The ultrastructural changes of small intestinal mucosa were observed by transmission electron microscopy.The lelves of DAO,D-lactate,and FABP2 in plasma were detected with ELISA method.4.Detection of intestinal flora:The contents of Escherichia coli,Enterococcus,Bifidobacterium,Lactobacillus,Bacteroides fragilis and Clostridium tenella in the rat feces of each group were detected by real-time quantitative PCR.Result:1.Compared with the control group,serum iron,serum ferritin,HEPC and liver iron concentrations of model group were significantly increased,the expression levels of DMT1and FPN1 were decreased significantly in model group?P<0.05?.While the expression of DMT1 and FPN1 were significantly higher in aplysin+iron,and the serum iron,serum ferritin,HEPC and liver iron concentrations were decreased?P<0.05?.2.As HE staining indicated,after rats were exposed by excessive iron in a long-term time,intestinal villus and glands were damaged significantly,a large number of mucosal epithelial cell falls off,mucosal epithelium and lamina propria separation.However,the pathological injuries were improved with the intervention of Aplysin.Transmission electron microscopy showed that in the control group,the structure of small intestine was clear and complete,the villi were arranged neatly and tightly,and the cells were tightly connected.In the model group,intestine microvillis were sparsed,intestine microvillis fell away,cell connection structures were incomplete even disappear.3.As intestinal barrier function testing:compared with the control group,the contents of D-lactate,DAO and FABP2 in aplysin group were was no significant difference?P>0.05?,the levels of D-LA and FABP2 were increased significantly in model group?P<0.05?.Compared with the model group,the levels of D-LA and FABP2 were decreased significantly in the Aplysin+iron group?P<0.05?.4.Compared with the control group,the content of Escherichia coli was significantly increased in the model group?P<0.05?.Compared with model group,the amount of Escherichia coil was reduced significantly,the amounts of Bifidobacterium and Clostridium tenella were elevated significantly in the aplysin+iron group?P<0.05?.Moreover,there was no significant difference between control group and aplysin group in all these indicators?P>0.05?.Conclusion:Aplysin exhibited regulative and protective effect on iron metabolism disorder and intestinal mucosal damage induced by excessive iron exposure in rats.The mechanism may be related to the regulation of the level of serum HEPC and the expression of DMT1 and FPN1 and the optimization the microbial structure.The mechanism of protecting intestinal health needs further study.