| Small veins appear gradually after endoscopic treatment and eradication of esophageal varices, which owes to late rebleeding. There is still no suitable method to treat these small newly visible veins because they are thin and serpentine. In this study we evaluated the effect of photodynamic therapy (PDT) on destruction of endothelial cells and obliteration of rabbit auricular veins to investigate its potential in treatment of esophageal varices.Endothelial cells of human umbilical vein (ECV304) were cultured in DMEM medium containing 10% fetal bovine serum. MTT colorimetric assay was used to screen out the suitable dose of photodynamic therapy on cultured cells. Photodynamic therapy were carried out on cultured cells (10 ug/ml of hematoporphyrin monomethyl ether and 10 minutes of irradiation by copper vapor laser at power density 15 mW/cm2) with normal cells to be control. Cells were cultured on 6 well plates with glass slice and then stained with Gimmsa dye to show the morphologic change. Cells were cultured on 24 well plates and samples were taken every day for 6 days to view the growth curves. Cells were cultured in 50 cm2 flask and then double stained with Annexin V/PI to test apoptosis on flow cytometer.Normal endothelial cells were shuttle-shape or multi-angle-shape. Cells of mitosis stage could be seen now and then. After photodynamic therapy the cells became small and round with unclear structure. Cells of mitosis stage could rarely be seen. Density of cells decreased. Normal endothelial cells entered exponential growth stage from the 2nd day of culture, showing an "S" shape growth curve. After photodynamic therapy endothelial cells grew slowly and decreased from the 2nd day of culture, showing a low level growth curve. Apoptosis detection suggested higher cell apoptosis rate (19.69% ?2.45%) after photodynamic therapy than that of normal cells (4.19% ?0.17%, P=0.001).In animal experiment pure-blood New-Zealand rabbit were used. Auricular marginal veins were irradiated using copper vapor laser after intravenousinjection of hemato- porphyrin monomethyl ether. Thrombus formation rates between groups of different dose were compared to screen out the suitable dose of photodynamic therapy on veins.When concentration of hematoporphyrin monomethyl ether was 10mg/kg, thrombus formation rate of group of 150 mW/cm2 and 40 minutes of irradiation (360 J/ cm2) was 6/7, which was higher than that of group of 180 J/ cm2 and 240 J/ cm2 of irradiation (P=0.001, P=0.041) and was believed to be suitable dose for obliteration of veins. Thrombus formation rate of group of 30mg/kg of hematoporphyrin monomethyl ether was higher than that of group of 10mg/kg and 20mg/kg (P=0.010, P=0.041) when energy density was 180 J/ cm2. But such a high dose of hematoporphyrin monomethyl ether was not suitable for clinical practice.Photodynamic therapy was then carried out on auricular marginal veins (irradiation of copper vapor laser at power density 150 mW/cm2 for 40 minutes instantly after intravenous injection of 10 mg/kg of hematoporphyrin monomethyl ether) with 3 control groups including rabbits receiving irradiation only, receiving injection of photosensative agents only and receiving injection sclerotherapy (sodium morrhuate). The treated place was observed macroscopicly and detected with ultrasonic microprobe. Biopsies were also performed and specimens were examined under microscope. Victoria blue stain was performed in addition to hematoxylin./eosin stain.Thrombus of the auricular marginal veins were formed and blood flow were obstructed at the irradiated place after photodynamic therapy. 4 week later, the thrombus were replaced by fibrous tissue and blood of distal end flowed back through collateral veins. No change of the veins was observed in control group of irradiation only or injection of photosensative agents only. In group of sclerotherapy auricular marginal veins turned blue instantly after injection of sclerosant and necrosis of adjacent tissue were found soon after. 4 weeks later there were larg...
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