Internal And External Biliary Drainage Inlfuence On The Bile Acid Receptor GP-BAR1Expression Of The Intestinal Mucosa In Rats With Obstructive Jaundice

【Backgrounds】Obstructive jaundice (OJ) is a common disease. It mayadvanced to sepsis and MODS in some conditions. Recent studies shows thatfunction of intestinal mucosal barrier play key roles in OJ and may influence thepatients’ prognosis. In the process of OJ, enterogenic infection is prone to occureif the bacterial or endotoxin translocate from the damaged intestinal mucosa. So, itis important to explore the effect of intestinal mucosa barrier on the progression ofOJ. Two ways were usually used to relieve biliary obstruction: internal biliarydrainage (ID) and external biliary drainage (ED). Studies shows that ID issuperior to ED. ID can decrease enterogenic infection ratio and endotoxin-relatedcomplication by promote intestinal mucosa recovery and recovery enterohepaticcirculation of bile acid. Our series studies in OJ rat model showed that infection,immune injury and hepatic dysfunction can recover by ID, but not by ED,however, the mechanism is unclear. GP-BAR1is bile acid-activated receptor anddistributes widely in different organs and gastrointestinal tract, which plays animportant role in physiological manipulation. We speculate that GP-BAR1couldbe connected with the intestinal mucosa immune function, which can induce bybile acid as a signaling molecule.【Aims】This study investigated the changes in four groups(OJ, ED, ID and SH)of intestinal mucosal tissue morphology, the mRNA and protein expression ofGP-BAR1receptor in intestinal mucosa, and further【METHODS】Sixty male adult Sprague-Dawley rats were used in this study.They were divided into4groups: sham operation (SH, n=15), common bile ductligation created obstructive jaundice (OJ, n=15), portion of OJ followed by external biliary drainage (ED, n=15), and part of OJ followed by internal biliarydrainage (ID, n=15). Animal models were successfully established via twiceoperations. The rats of OJ and SH groups were executed and specimens of ilealtissue were obtained on the8th day from the first operation, where after ED andSH groups were taken on the15th day from the first operation. The terminal ileumspecimens of each group was obtained for observation of haematoxylin-eosin (HE)staining. GP-BAR1of the ileum mucosa were analysed by Western blot andreverse transcription-polymerase chain reaction (RT-PCR).【Results】The protein expression of GP-BAR1was increased significantly in theintestinal mucosal of OJ group, which was higher than that of in SH group(OJ vsSH,0.641±0.087vs0.398±0.062，P＜0.01). After Internal and external biliarydrainage to alleviate OJ respectively, the GP-BAR1expression was decreasedsignificantly in ID group, similar with SH group (ID vs OJ,0.447±0.057vs0.641±0.087，P＜0.01; ID vs SH，0.447±0.057vs0.398±0.062，P＞0.05), andlower than that of in ED group (ED vs OJ,0.597±0.093vs0.641±0.087，P＞0.05). The GP-BAR1protein expression was difference between ED group and IDgroup (ED vs ID，0.597±0.093vs0.447±0.057，P＜0.01) and that was similarbetween ED group and SH group (ED vs SH，0.597±0.093vs0.398±0.062，P＜0.01). Further research showed that the expression of GP-BAR1mRNAincreased significantly in OJ rats (OJ vs SH,0.796±0.114vs0.407±0.072，P＜0.01). After relieving of OJ, the mRNA expression of GP-BAR1in ID group wasdecreased, similar with the levels in SH group (ID vs OJ，0.483±0.107vs0.796±0.114，P＜0.01; ID vs SH，0.483±0.107vs0.407±0.072，P＞0.05). ThemRNA expression of GP-BAR1was not decreased significantly in ED groupwhen compared with SH(ED vs OJ，0.729±0.134vs0.796±0.114，P＞0.05; EDvs SH，0.729±0.134vs0.407±0.072，P＜0.01), and with ID (ID vs ED，0.483±0.107vs0.729±0.134，P＜0.01).【Conclusion】The mRNA and protein expression of GP-BAR1in intestinalmucosa were increased in OJ group. ID can reduce GP-BAR1expression significantly than ED These findings show that ID may improve the recoveryintestinal mucosa barrier by influence the expression GP-BAR1.