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Objective To study the effect of BCL-2 ?-radiation on BCL-2 gene in dogs, and its relationship and signifcane on apoptosis of proliferated smooth muscle cells of bile duct wall. Methods The ~(103)Pd (radioactivity) stent(experiment group) or ordinary stent(control group) was positioned into the target segment of bile duct. The injured bile duct segments were dissected free from the dogs, and BCL-2 gene in the (control) and r-radiation-induced apoptotic smooth mucle cells of bile duct wall was analysed by using (immuno-histochemical) technique. The number of apoptotic cells was counted, and size of lumen of bile duct in both groups was measured by a computerized imaging system.Results BCL-2 gene expression was weaker in the ~(103)Pd radioactive stent group than in the ordinary stent group. The group of dogs with low expression of BCL-2 genes showed marked apoptosis of proliferated smooth mucle cells of bile duct and there was no overt stenosis of extrahepatic bile ducts. The group that showed high expression of BCL-2 gene did not show marked apoptosisi of proliferated smooth muscle cells of bile duct, and there was marked stenosis of extrahepatic bile duct.Conclusions The expression level of BCL-2 in experimental dogs is related to the develoment of (cellular) apoptosis and to radiation sensitivity of the cells. ~(103)Pd radioactive stent can reduce the expression of BCL-2 gene, promote apoptosis of proliferated smooth muscle cells of bile duct, and suppress stricture (formation) of extrahepatic bile duct.
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Objective To study ?-radiation-induced expression of Fas gene and its significance in the apoptosis of proliferative muscle cells of bile duct wall in dog model. Methods The ~ ~103 Palladium (Pd) radioactive stent or general stent was inserted into dog extrahepatic bile duct, and bile duct specimens were ~obtained after 30 days. Expression of Fas and apoptosis of bile duct muscle cells in the control and ?-radiation-~induced groups were determined by immunohistochemical technique. The square of bile duct cavities of two groups were measured by computer ~imaging detecting system. Results The ~expre- ~ssion of Fas was much higher in the bile duct wall of dogs with ~ ~103 Pd radioactive stent than that in dogs with the general stent, and apoptotic muscle cells were more common in Fas highly expreessed than that in the Fas lowly ~experssed subgroup, and no stricture of extrahepatic bile duct was seen in former subgroup. No obvious ~apoptotic muscle cells were observed in the Fas lowly expressed subgroup, however, the dog in this ~subgroup had the obvious stricture of extrahepatic bile duct. Conclusions The level of Fas gene expression was associated with the rate of cell apoptosis in dog bile duct wall, and the ~ ~103 Pd radioactive stent may increase the expression of Fas gene, enhance the apoptosis of proliferative muscle cells of bile duct, and therefore prevent the stricture of extrahepatic bile duct.
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Objective To investigate the preventive effects of 103 Pd radioactive stent on stenosis after bile duct injury in dogs.Methods Twelve healthy dogs (15～20kg) were randomly divided into 103 Pd radioactive stent group (n=6) and control group (n=6). Immediately after balloon dilatation injury to the bile duct, the 103 Pd radioactive stent(experiment group) or the ordinary stent(control group) was positioned into the target segment. The dogs were killed one month later. The injured bile duct segments were dissected free from the dogs, and were examined radionucleonically, immunohistochemically and pathologically. Muscular proliferation area and lumen area were determined by computer assisted picture analysis system. Results In the control group, 30 days after ductal injury, the mucosa of the bile duct was fractured, the mucosa was proliferated and the lumen stenosed.Compared with the control group, 103 Pd radioactive stent significantly reduced muscular proliferation area (P