Objective To investigate the effects and significance of nerve growth factor (NGF) and its high affinity receptor of tyrosine kinase A (TrkA) expressions on proliferative connective tissue of bile duct in rats after bile duct ligation (BDL). Methods Forty-six female Sprague-Dawley rats were randomly divided into two groups: control group ( n =6) and BDL group ( n =40). The model of obstructive jaundice in rat was made by bile duct ligation, then duodenohepatic ligament was taken and treated with anti-NGF and anti-TrkA receptor antibody. Expressions of NGF and TrkA receptor in connective tissue of bile duct were investigated by immunohistochemistry, blood specimens were collected from left ventricle to detect serum total bilirubin (TB) and alanine aminotransferase (ALT). Results After BDL, TB level obviously elevated in the third day, and continued until the fourteenth day, then descended. By day 21 and 28, it returned to normal level. Compared with normal bile duct, due to bile stasis, an increased thickness of the bile duct wall was observed by microscope which correlated with the proliferation and differentiation of connective tissue cell. NGF and TrkA were expressed by the cell membrane and the cytoplasm of connective tissue cell and inflammatory infiltration cell after BDL. The trend between their expressions and bilirubin levels was similar. Conclusion NGF and its receptor TrkA regulate the proliferate and differentiation of connective cell in bile duct. They may play a key role in the formation of bile duct scar, which seems to be hardly reversed by relief of bile stasis in a short time.
ObjectiveTo investigate the synergistic antitumor effects of ionizing radiation and the cytosine deaminase (CD)/5-flurocytosine (5-FC) system therapy in human pancreatic cancer cell.MethodsThe expression vector containing CD was transfected into the human pancreatic cancer cell line PC3. The clones were picked out after G418 selection. The CD gene integration and expression were confirmed by the RT-PCR. The cytotoxicity to the cells with or without CD and (or) ionizing radiation under the treatment with 5-FC was measured by the MTT assay. The clonogenic assay was used to investigate the radiosensitizing effect of 5-FC on the PC3 cells transfected or untransfected with CD gene.ResultsThe CD gene was stably expressed in the PC3 cells transfected with CD gene. The cytotoxic effect of 5-FC was superior on the PC3 cells transfected than that of untransfected with CD gene (P<0.05) and which were enhanced in combination with the ionizing radiation (P<0.05). The CD/5-FC enhanced the radiosensitivity of PC3 cells transfected with CD gene (P<0.05). The change in the radiosensitivity was quantified by calculating the sensitization enhancement ratio (SER) at the clinically relevant dose of 2 Gy. The SER was 1.5 in the PC3 cells transfected with CD gene by giving ionizing radiation of 2 Gy.ConclusionsCD/5-FC system is a potenial radiosensitizer in PC3 cells transfected with CD gene. Ionizing radiation and CD/5-FC system is more effective for killing effect of PC3 cells than ionizing radiation or CD/5-FC system alone.