ABSTRACT
Present study aimed to investigate the eff ect of curcumin-pretreatment on intestinal I/R injury and on intestinal mucosa barrier. Thirty Wistar rats were randomly divided into: sham, I/R, and curcumin groups (n=10). Animals in curcumin group were pretreated with curcumin by gastric gavage (200 mg/kg) for 2 days before I/R. Small intestine tissues were prepared for Haematoxylin & Eosin (H&E) staining. Serum diamine oxidase (DAO) and tumor necrosis factor (TNF)-alpha levels were measured. Expression of intestinal TNF-alpha and tight junction protein (ZO-1) proteins was detected by Western blot and/or immunohistochemistry. Serum DAO level and serum and intestinal TNF-alpha leves were signifi cantly increased after I/R, and the values were markedly reduced by curcumin pretreatment although still higher than that of sham group (p<0.05 or p<0.001). H&E staining showed the significant injury to intestinal mucosa following I/R, and curcumin pretreatment signifi cantly improved the histological structure of intestinal mucosa. I/R insult also induced significantly down-regulated expression of ZO-1, and the eff ect was dramatically attenuated by curcumin-pretreatment. Curcumin may protect the intestine from I/R injury through restoration of the epithelial structure, promotion of the recovery of intestinal permeability, as well as enhancement of ZO-1 protein expression, and this eff ect may be partly attributed to the TNF-alpha related pathway.
Subject(s)
Animals , Amine Oxidase (Copper-Containing) , Blotting, Western , Curcumin , Eosine Yellowish-(YS) , Immunohistochemistry , Intestinal Mucosa , Intestine, Small , Intestines , Permeability , Rats, Wistar , Reperfusion Injury , Tight Junctions , Tumor Necrosis Factor-alpha , Zonula Occludens-1 ProteinABSTRACT
Objective To detect the changes of visceral sensitivity in rats presenting intestinal dysbacteriosis and the expressions of tight junction protein (ZO-1)and Toll-like receptor 4 (TLR4)so as to explore the effect of intestinal dysbacteriosis on visceral sensitivity and the possible mechanisms.Methods We randomly divided 30 male SD rats of SPF grade into normal control group (n = 12 )and dysbacteriosis group (n = 18 ).Rats in dysbacteriosis group were administered with lincomycin hydrochloride (300 mg/mL),1 mL each time per rat once a day for 7 consecutive days;those in normal control group were fed with the same amount of saline.On the eighth day,six rats were randomly selected from normal control group and dysbacteriosis group respectively to detect whether the model was successful.After the model was successfully constructed,the remaining 12 dysbacteriosis rats were randomly divided into the negative control group and the probiotics intervention group with 6 in each.Rats in the intervention group were given probiotic bifidobacterium triple viable capsules (Bifico)orally,one capsule with 1/3 mL of saline,1 mL each time per rat once a day for 7 consecutive days;those in the negative control group received the same amount of saline.On the eighth day,fresh feces was cultured for flora to detect visceral sensitivity by abdominal withdrawal reflex (AWR),the mRNA and protein expressions of ZO-1 and TLR4 in the colon,and the expression of serum inflammatory cytokines IL-10 and TNFα.Results The expression of ZO-1 in the colon was significantly lower in the rats of dysbacteriosis group than those in the control group,and the expression of TLR4 was also significantly increased.Correspondingly,the expression of pro-inflammatory factor TNFα in the serum of the rats in dysbacteriosis group was significantly increased,while that of anti-inflammatory factor IL-10 was significantly lower than in the control group (P <0.05).Furthermore,compared with dysbacteriosis group,the expression of ZO-1 was increased significantly and TLR4 was decreased in probiotics group in varying degrees. Similarly,the expression of TNFα was obviously lower while that of IL-10 in the serum was higher (P < 0.05 ). Conclusion Inhibiting the expression of ZO-1 and increasing the expression of TLR4,thus leading to chronic low-grade inflammation, may be one mechanism of visceral hypersensitivity caused by intestinal dysbacteriosis. Probiotics may restore the dysbacteriosis and thus improve visceral hypersensitivity.