The Abnormal Expression Of Fas/Fas-L And TGF-β₁in Liver Tissue In Biliary Atresia And Its Clinical Significance

Background:Biliary Atresia (BA) is one of the main causes of Neonatal obstructive jaundice. The incidence of the disease is about1per5000to14000of live births, however that is relatively high in China and Japan. The progressive lesions can lead intrahepatic and extrahepatic bile duct to be occlusive. Cirrhosis appears rapidly if the patients aren’t treated in time.The occurrence and development of biliary atresia are associated with ductular reaction and fibrosis. During the fetal period or after birth, the bile duct cells is injuried and apoptosis by a variety of stimuli and damage of virus or dysimmunity. And reactive secretion of cytokine induced activation of hepatic stellate cells (HSC) that produce a large amount of extracellular matrix (ECM) depositing in the portal tract, leading to cholestasis and inflammatory stimulation, and accelerating the progress of liver fibrosis. Fas antibodies can prevent the apoptosis of HSC which is normal or has entered apoptotic cycle. Using Fas to activate the antibodies can significantly increase the number of apoptotic cells. Liver fibrosis in BA occur early, develop rapidly, and are important prognostic factors in children. TGF-β can promote liver fibrosis, so the inhibiting of generation or biological function of TGF-β are important to the prevention and treatment of hepatic fibrosis.The liver tissue in BA were studied by immunohistochemical staining for semi quantitative and transmission electron microscope technology, that should be to approach the relationship between Fas/Fasl and TGF-β1and bile duct epithelial apoptosis、proliferation and hepatic fibrosis.Patients and controls:Ten patients with BA were enrolled and all of them had been performed operation and confirmed with Pathological examination from July2005to October2007. Four cases of normal control are all without liver disease.Methods:One pieces of1.0cm*0.5cm*0.5cm was got from lower edge of the right hepatic lobe, Putting half piece into formalin liquid (PH7.4.) fixed for12hours, using immunohistochemical staining Envision of two paces for Fas、FasL and TGF-β1measurement. Put the other half with2.5%glutaraldehyde solution fixed at4℃, then it should be observed under the TEM.The results of immunohistochemical will be tested by two samples level and inspection of nonparametric statistics (Mann-Whitney Test). Also the outcome will be analyzed by using SPSS13.0software process.Results:1. Fas expression cytoplasm and cell membrane. It shows strong positive expression in liver cell cytoplasm and bile duct epithelial cells. The positive expression was found in portal area of inflammatory cells which are infiltrated. It was negative in control group.2. Fas-L expressionIt was main expression in hyperplasia bile duct epithelial cells and liver cell cytoplasm. None of the four cases showed any expression.3. TGF-β1expressionIt was main expression itself on the hyperplasia of the bile duct epithelial cells or near the portal area of liver cell cytoplasm. It showed expression Both in liver cells and bile duct epithelial cells. One case of the four normal comparison cases shows weak positive expression, the other three cases show negative.4. The extent of Fas/Fas-L、TGF-β1expressionsFas、Fas-L、TGF-β1had expression in10cases of biliary atresia liver tissue cells. And the outcome was higher than other normal controlling cases (p<0.01). The level of expression was positive correlation with the degree of the aggravating of the bile duct epithelial hyperplasia (r1=0.6354, p1<0.05; r2=0.7031, p2<0.05). The TGF-β1expression should improve following the augmentation of the degree of liver fibrosis (r=0.8333, p<0.01), and also the level of liver fibrosis has the positive correlation with the bile duct epithelial (r=0.9578, p<0.001).5. The situation of TEM observation:The destruction phenomenon of the liver cells were observed in BA group. There were numbers of cavity and dense deposit in the cells, and also with the cytoplasm organelles damaged, mitochondrial membrane destroyed and the lesser number of mitochondria. The hepatic cell nucleus appear like an apoptosis phenomenon with no structure. This phenomenon appears more in ECM, many fiber organizations can be found around liver cells or the portal area, with the increasing number of capillary, and also the joint can be found destroyed. The degree of damaging in bile duct epithelial was varied with the proliferation, meanwhile, the apoptosis phenomenon occurring also.Conclusion:1. Hyperplasia of the bile duct epithelial is related to the expression of Fas、Fas-L2. Liver fibrosis is related to the expression of TGF-β1.3. The proliferation degree of the BA bile duct epithelial is related to the level of liver fibrosis. Proliferation of bile duct promotes liver fibrosis.