The Distribution And Significance Of CHAT Gene And NNOS Gene In The Duct Wall Of Congenital Choledochal Cyst

Purpose: Congenital choledochal cyst (CCC),which represents as bileduct dysexpansion, is a kind of Congenital common bile duct dysplasia inchildren, distal extrahepatic biliary stenosis, tube wall hypogenesis andanomalous junction of pancreaticobiliary duct have been considered to playimportant roles in cholestasis and discharged obstacles,all these factorscontribute to bile duct dsyexpansion. Congenital choledochal cyst in infancyonset accounted for2/3,1/3in young, male to female is about1:4to5[1]. Sofar, the cause of congenital bile duct cysts is still not very clear, in recent years,with the progress of the study of the morphology of the disease, bileenzymology and animal experiments, recognized that CCC is caused by avariety of factors, and nerve, muscle dysplasia pathogenic factors in distalsegments of the common bile duct has been increasing. Distribution of nerveconsists of internal and external biliary wall nervous system of the biliary tract,which adjust the function of biliary tract coordinately. Studies have shown thatthe main neurotransmitters regulating biliary include excitatory neurotransmitterAch and inhibitory neurotransmitter NO, but the distribution of different neu-rotransmitters in CCC cyst lesion and its relationship with different types ofcyst is still not very clear. This study by using RT-PCR method, contrastedamong different parts of CCC extrahepatic biliary about the expressions of thekey enzyme in synthesising inhibitory neurotransmitter NO-Neuronal NitricOxide Synthase (nNOS) and excitatory neurotransmitter Ach-Cholineacetyltransferas (CHAT) in the neural network structure, to explore the effectof enteric nerve abnormal regulation role in the pathogenesis of CCC based onthe gene level and neural motivation, to fill up the mechanism of CCC furthermore, providing important theoretical basis for its clinical treatment. Methords:20cases with CCC,6males and14females(1:2.3), were un-derwent surgical treatment in this study in department of pediatric surgery ofthe Second Hospital of Hebei Medical University from January2011to Sep-tember2012. The mean age was4.33±2.94years with a range from8monthsto11years. Of the20cases,12cases with abdominal pain,4cases presentedjaudice and white stool,2cases with fever,1case had biliary tract perforation,1case was found by antenatal ultrasonographic investigation.All of themdiagnosed clearly by ultrasonographic investigation or computed tomographyin preoperation.20cases underwent resection of choledochal cysts andgallbladders and practiced hepaticojejunmRoux-Ystomy or hepaticoduode-nostomy.The study took the wall of gallbladders, the proximal and distal seg-ments of duct cysts as3groups. Three groups of specimens were frozen inliquid nitrogen and stored at-70℃. The expressions of nNOS mRNA andCHATmRNA were detected by real-time quantitative PCR in different groups.Statistical analysis was performed by SPSS13.0software package. Aprobability level of5%(P＜0.05) was considered significant.Results: The expressions of nNOS mRNA and CHATmRNA weredetected by real-time quantitative PCR in parts of CCC, these indicators havedifferent expressions in each group. The expressions of CHAT and nNOS inproximal segments of CCC were1.38±0.21,1.65±0.16, the indexes above-mentionedexpressed in distal segments of CCC were1.79±0.21,1.15±0.17, meanwhile, ingallbladders of CCC were1.30±0.19,1.57±0.12, in distal segments of cystictype were1.74±0.21,1.11±0.15, in distal segments of fusiform type were1.86±0.20,1.22±0.18. Statistical analysis found that compared to the expression ofCHAT in distal segments of CCC, the expression of CHAT in proximalsegments and in gallbladders of CCC were all weaker(P <0.05),but there wasno statistical significance between the expression of CHAT in proximalsegments and in gallbladders of CCC (P>0.05). Compared to the expressionof nNOS in distal segments of CCC, the expression of nNOS in proximalsegments and in gallbladders of CCC were all more(P <0.05),but there was nostatistical significance between the expression of nNOS in proximal segments and in gallbladders of CCC (P>0.05). In the end, there was no statistical sig-nificance about the expressions of all above mentioned indexes in distal seg-ments between cystic type and fusiform type (P>0.05).Conclusions:1.The expression of CHAT gene in distal segment is morethan the proximal and gallbladder in CCC, which shows that the distributionof excitatory cholinergic nerve relatively increased in the distal of congenitalcholedochal cyst, resulting in circular smooth muscle spasmodic contraction inthe distal bile duct, leading to the pathogenesis of CCC.2.The expression of nNOS in proximal segments and in gallbladders ofCCC are all more than in distal segments,which illustrates that the distributionof inhibitory nerve in the distal decreases and the smooth muscle in distal re-laxation is limited, which results in the formation of choledochal cyst.3.There is no statistical significance between the expressions of CHATand nNOS both in proximal segments and in gallbladders of CCC, which sug-gests that the distal segment of CCC is the major pathological point.4.There is no statistical significance about abnormalities distribution ofexcitatory and inhibitory neurotransmitter in the different pathological types ofCCC.