光动力作用对活体肝组织损伤研究

A Study on Liver Damage Induced by Photodynamic Therapy

目的 研究光动力作用对活体肝组织的损伤 ,探讨光动力治疗肝癌的可行性 ,为临床治疗提供实验依据。方法 动物实验 :将小鼠分成光动力疗法 (PDT)组、单血卟啉衍生物 (HpD)组、激光组和空白对照组。光敏药物选用血卟啉衍生物 ,给药量每公斤体重 10mg ,药物用 1ml生理盐水稀释 ,于实验前 48h将药物注射入PDT组和HpD组小鼠腹腔内 ,避光饲养。将PDT组和激光组小鼠固定于实验板上。麻醉后 ,剖腹暴露右肝前叶 ,激光直接投照于肝脏表面 ,光斑直径 5mm ,照射 2min。激光器为氩离子泵浦染料激光器系统 ,光波长 6 30nm ,输出功率 10 0mW ,每一照射区能量累积约 6 0J ,照光后关腹 ,回笼饲养观察。于照光后 1、2 4、72、12 0h处死各组小鼠 ,剖腹取肝组织置于 4%福尔马林液中固定 ,常规石蜡包埋切片 ,HE染色 ,光镜观察。临床治疗 :经病理确诊的肝癌患者 ,于治疗前 48h做皮肤划痕试验 ,阴性者按每公斤体重 5mg静脉给药。治疗时 ,在B超引导下 ,用 18G肝穿针经皮穿刺 ,将石英光纤导入肝肿瘤内。激光波长 6 30nm ,输出功率 35 0mW ,每一照射点能量累积2 2 0J。治疗 1个月后行二期切除术。标本用 4%福尔马林固定 ,常规石蜡包埋切片 ,HE染色 ,光镜观察。结果 动物实验光镜观察结果显示 :PDT组于照光后 2

Objective To investigate the liver damage induced by photodynamic therapy(PDT) and provide an experimental basis for PDT treatment for liver cancers. Methods 96 normal mice were divided into 4 groups: PDT group, laser group, HpD group and control group. The photosensitizer used in this study was hematoporphyrin derivative (HpD), diluted in 5% glucose and injected into the peritoneal cavity at a dose of 10 mg/kg body weight 48 h before light irradiation. The mice were kept from sunlight exposure. After anesthesia the abdomen was opened and the right front lobe of the liver was exposed. An argon laser pumped dye laser system was used. The liver surface was directly irradiated by the 630 nm laser beam at a power of 100 mW for 2 minutes. The spot size was 5 mm in diameter and the energy density was 60 J/cm 2. The mice were killed at 1, 24, 72 and 120 hours after laser irradiation, respectively. Samples were embedded in paraffin and HE stained sections were examined underlight microscope. Besides, a 46-years old male patient with liver cancer was also included in this study. He received HpD in a dose of 5 mg/kg body weight, i.v. injected 48 h prior to laser irradiation. Ultrasound-guided liver puncture was performed and optical fibers were inserted into and evenly distributed in the tumor. The 630 nm laser irradiation was carried out at a power of 350 mW, energy density of 250 J/cm 2 per each spot. The patient was operated one month later and specimens were taken for histopathological examination. Results Animal experiment: Large necrotic areas were observed in livers of mice 24 hours after PDT. There was a clear demarcation between irradiated and non-irradiated areas observed by both gross and microscopic examination. Fibrous proliferation was seen in the surrounding tissues 120 hours after PDT. Swelling of hepatocytes was observed at 1 h after laser irradiation alone, but returned to normal at 72 h after irradiation. No damage to hepatocytes was observed in livers of both HpD alone and control groups. Clinical case: Wide-spread necrotic areas were present in the PDT irradiated tumor tissue. Normal hepatocytes were observed in the non-irradiated surrounding tissue. There were numerous lymphocytes and macrophages infiltrating in the surrounding areas. Conclusions Selective and sharply demarcated photodamage to liver tissue can be induced by selective laser irradiation after HpD administration. It is suggested that photodamage to surrounding normal tissues can be avoided by carefully controlled laser irradiation during photodynamic therapy of liver cancers.