The Protective Effect Of Glycine On The Intestinal Barrier Of Rats With Obstructive Jaundice

Obstructive jaundice is a frequent clinical matter in the generalsurgery, whose basic pathological change is the obstruction of biliarytract. It can induce the severe pathophysiological changes of bloodsystem, immune system and some important organs. It has beenshowed that endotoxemia plays a big part in damaginng the organicfunction of obstructive jaundice patients. Moreover one main factorwhich can result in the high mortality rate and complications isendotoxemia when the patients are receiving the traumaticexaminations and treatments. Therefore, degrading the incidence ofendotoxemia has became the main study direction on relieving themultiorganic pathoimpair which results from the obstructive jaundice.The main factor which induces the endotoxemia is the damage ofenteric barrier.Then enteric bacterias and their endotoxin can enter theblood through the destructive enteric barrier and aggravate the injureof enteric epithelium, which leads to the vicious cycle. How to relivethis kind of injury is a important problem we have to solve in theclinical work. But there were few studies about the enteric barrier ofobstructive jaudice. Recently, more and more investigations haveshowed that glycine has protection for many organs, tissues andcells.However, at present the effect of glycine on improve thefuncution of enteric barrier of obstructive jaundice was seldomreported. This problem is studied in this investigation. Objective: Discuss the protection and mechanism of glycine onenteric barrier of experimental obstructive jaundice. Methods: 60 standard even-aged male Wistar rats whose body weights are 220-260 gram were chosen and were devidede in three groups at random, there are 20 rars in every group.Group A (SO): The rats in this group had been fed with stardard feedstuff and drinking water for 5 days before the operations. The rats were given the intraperitoneal anesthesia with 2% Pentobarbital (45mg/kg). Following the laparotomy, the liver was removed surgically and then the duodenohepatic ligament was exposed and liberated inactively after the anesthesia. We didn't ligate the bile duct and closed the abdominal cavity. The operation was over; Group B (BDL): The operating procedure was the same as Group A except that the bile duct was ligated double to form a complete obstruction of the extrahepatic bile duct; Group C (BDL+Gly): The animal models were the same as Group B. But the rats had been fed with 5% glycine solution for 5 days. From the second day after the operation, the rats in the three groups were fed according to the preoperative standard. After 3 weeks, the rats were put to death with anesthesia. We opened the abdominal cavities of the rats and observed the appearance and representation of the organs under the sterile conditions. The samples of ophthalmic venous blood were put into the sterile tubes respectively. The20-centimeter end-piece ileums were prepared and cleaned in thesterile normal saline. Some of them were stored at -70℃until use,others were fixed in 10% formalin solution. To measure the indexesaccording to the following methods: (1) Measure the BIL with theautomatic biochemistry analyzer. (2) The fixed samples in the 10%formalin solution were taken out, dehydrated with alcohole, embeddedwith paraffin and sliced. After HE dyeing, we observed thehistomorphological variance under the light microscope. (3) Measurethe height of the intestinalvillus and thichness of mucosa withMPIAS2500 analytical system. (4) Measure the concentration of NOthrough measuring the concentration of NO2 .Statistical analysis: -Results were expressed as X士S. Experimental data were processed byanalysis of variance and t-test for comparison between groups. Results: The jaundice was observed on the ear and tail end skinin few rats of Group A on the 4th day and all over the body in the mostrats of A on the 7th day, whose urine was deep yellow. The experimentwasn't stopped until the bile duct had been ligated for three weeks.The utmost dilation of proximal bile duct at the site of ligation, thevery thin bile tract wall, and deep-brown-coloured liver were observedthrough laparotomy. Plasma BIL levels in rats of Group B and GroupC were significantly increased compared with that in rats of GroupA(P<0.01). The animal models were established successfully.Compared with Group A, the level of NO in intestinal tissue of GroupB rats was significantly elevate(P<0.01), the height of intestinal villiand the mucosal thickness in Group B rats were significantly degraded(P<0.01) and intestinal tissue in the rats of Group B was injured.Compared with A, there was no significant difference of the level ofNO in intestinal tissue of Group C rats (P >0.05). There was nosignificant difference of the height of intestinal villi and the mucosalthickness between rats in Group B and A (P>0.05). Compared withGroup B, the level of NO in rats of Group C is lower(P<0.01), theheight of intestinal villi and the mucosal thickness is higher(P<0.01),the injure of intestinal tissue is lighter. The fuscous pigmentary wasobserved on the mucous membrane of small intestine of obstructivejaundice rats. Under the light microscope, normal rats'intestinalmucosalthickness was normal and intestinal villus lined up in order.The intestinal mucosal thickness of obstructive jaundice rats becamethin obviously and is one third or half of that in rats of Group A. Theintestinal villus of obstructive jaundice rats were rare and the counts ofthe break, absorptive cells and goblet cells on the surface decreased.Inflammatory cell infiltration can be observed on the intestinal mucosa.The changes ,that the intestinal mucosa became thinner, in rats ofGroup C is improved compared with that in rats of Group B. Theintestinal thickness in most of rats of Group C is approximate to that ofGroup A and the rare intestinal villus had been improved. Conclusion: 1. the intestinal mucosal mechanical barrier ofobstructive jaundice rats was damaged severely, the level of NO in theintestinal tissue of obstructive jaundice rats was elevated significantly.2. Glycine can degrade the level of NO in the intestinal tissue andimprove the damaged intestinal mucosal barried obviously. It has been showed that the damaged intestinal barrier ofobstructive jaundice can induce the endotoxemia. At the same time theenteric bacteria and endotoxin enter blood, result in the endotoxemiaand then induce systemic inflammatorome reaction, which activate theneutrophils. The neutrophils release the cytokine and mediators ofinflammation such as NO, TNF-α, IL-6, INF-γ, oxyradical and soon, which aggravate the injury of mucosal barrier. At last, the viciouscycle is formed. Glycine can rival and inhibit endotoxin through thecombination of NH+3 on it and PO-4 on endotoxin, and then blocks theopen of calcium channel on the cellular membrane of monouclearmacrophage, which can prevent Ca2 + from inflowing and preventmonouclear macrophage from releasing the cytokine. So it is possibleto decrease the biological effect of endotoxin. The results have showed:(1) The level of NO in rats of obstructive jaundice is higher than thatin rats of Group SO, which shows that NO takes part in thecomplicated pathophysiological procedure and has significangt effecton damaging the intestinal mucosa. (2) Glycine can restrain theelevation of the level of NO which result from endotoxin and degradethe biological effects of endotoxin. Glycine in obstructive jaundice can...