Effects Of Relief Of Obstructive Jaundice By Internal And External Biliary Drainage On The Expression Of CD14 By Rat Kupffer Cells

[Backgrounds and Objective]Patients with obstructive jaundice(OJ) are often complicated with postoperative infection and septicemia,possessing a high mortality.Our previous study has found that a great amount of cytotoxic nitric oxide was produced by Kupffer cells in rats with OJ.The elevated nitric oxide could be suppressed by internal biliary drainage,but not by external drainage. However,the elevated plasma endotoxin in rats with OJ could be depressed not only by internal biliary drainage,but also by external drainage.The mechanism of the findings remains unclear yet.We proposed a hypothesis that CD14 as a receptor of endotoxin might play an important role in the immune suppression in O J,and related to the effects of biliary drainages.In this experiment,we studied the effects of internal and external biliary drainage on the expression of CD 14 by Kupffer cells in rats with OJ,in order to explore the mechanism of internal biliary drainage being superior to external drainage.[Methods]In the first part of the study,sixty male adult Sprague-Dawley rats were randomly assigned to four groups:OJ(n=15),internal biliary drainage(ID, n=15),external drainage(ED,n=15) and sham operation(SH,n=15).The expression of CD14 by liver Kupffer cells was measured as the semiquantitative values(the average integral optical density,IOD/area) by an image analysis system with an immunohistochemistry method.In the second part of the study,forty male adult Sprague-Dawley rats were randomly assigned to four groups(OJ group n=10,ID group n=10,ED group n=10,SH group n=10).Kupffer cells were isolated by a method of in situ hepatic perfusion and digestion with collagenⅣ. The expression of CD14 mRNA by the Kupffer cells was detected by reverse transcription polymerase chain reaction(RT-PCR) after the isolated Kupffer cells were cultured with endotoxin(10ng/ml) in vitro for 15 hours. [Results]The expression of CD14 by Kupffer cells was significantly stronger in OJ rats(0.015557±0.002135 IOD/area) than that in SH rats (0.001355±0.000822 IOD/area)(p＜0.01).The expression of CD14 by Kupffer cells was significantly reduced in 1D rats(0.001548±0.001024 IOD/area)compared with OJ rats(p＜0.01),but not reduced in ED rats(0.008570±0.001893 IOD/area)(ED vs OJ p=0.5907).These results indicated that internal biliary drainage could reverse the elevated expression of CD14 by Kupffer cells in OJ rats,but external drainage could not.Under the stimulation of endotoxin,the expression of CD14 mRNA by Kupffer cells was significantly increased in ED rats(6.104±2.171)compared with SH rats(1.388±0.683),OJ rats(1.998±0.740) and ID rats(1.018±0.489)respectively(p＜0.01).The difference of the expression of CD14 mRNA by Kupffer cells between ID and SH,OJ group was not statistically significant(ID vs SH p=0.944,ID vs OJ p=0.513).These results indicated that external biliary drainage could enhance the sensibility of CD14 genes to endotoxin,while internal biliary drainage could not.The expression of CD14 mRNA by Kupffer cells was not significantly increased in OJ rats compared with SH rats(p=0.822).This result might be related to the formation of mild cirrhosis occurred in OJ rats.[Conclusions]Internal biliary drainage is superior to external drainage in terms of reversing the elevated expression of CD14 by Kupffer cells in rats with obstructive jaundice and regulating the sensibility of CD14 genes to endotoxin. The mechanism of internal biliary drainage being superior to external drainage seems to be related to the transcription process of CD14 genes.