ANALYSIS OF CYTOTOXIC MECHANISMS OF ACTIVATED EOSINOPHILS IN BILIARY CELL INJURY : ESTABLISHMENT OF AN ANIMAL MODEL FOR PRIMARY BILIARY CIRRHOSIS

嗜酸性粒细胞活化是慢性排斥反应、移植物抗宿主病（GVHD）、原发性胆汁性肝硬化（PBC）等肝脏疾病的常见病理特征，在这些疾病中，嗜酸性粒细胞活化在肝脏损伤中起重要作用，但其确切机制尚未明确。使用IL-5转基因（IL-5 Tg）小鼠，我们首先建立了由活化的嗜酸性粒细胞引起的肝损伤的实验模型。IL-5 Tg小鼠（C3 H/HeN-TgN（IL-5）Imeq）已经建立并由高知医学院的DR.Tominaga提供。尽管该小鼠在外周表现出明显的嗜酸性粒细胞增多（30-70%），但在任何器官中均未观察到组织损伤。IL 5 Tg小鼠腹膜内注射25 μ g LPS（Salmonella minesota Re 595），2周后处死。组织学检查显示明显的门静脉炎症伴汇管区嗜酸性粒细胞浸润（>50%）和广泛的小叶周围坏死 ...更多信息 嗜酸性粒细胞一些小胆管变性和破坏，嗜酸性粒细胞聚集，其中嗜酸性粒细胞浸润到导管上皮细胞中观察到。电子显微镜检查显示嗜酸性细胞毒性颗粒脱颗粒进入导管细胞。在IL 5 Tg小鼠中几乎不存在肝脏以外的组织损伤。将来自用LPS致敏的IL 5 Tg的脾细胞（2 × 107个细胞;嗜酸性粒细胞>50%）静脉内转移到非转基因小鼠（C3 H/HeN）中，但从未诱导任何组织损伤。这一结果表明，除了活化的嗜酸性粒细胞外，另一种因素如LPS刺激的枯否细胞释放的各种细胞因子包括TNF α是诱导嗜酸性肝损伤所必需的。进一步分析与活化嗜酸性粒细胞趋化和脱颗粒有关的细胞因子或趋化因子的动态变化，对于理解该动物模型中的肝损伤是必要的。少

Activated eosinophilic infiltration is a common histological feature in diseased liver such as chronic rejection of transplanted liver, GVHD, or primary biliary cirrhosis (PBC) resembling chronic CVHD.In such conditions, it is suggested that activated eosinophils play an important role in liver damages, though precise mechanisms have not been analyzed. Using IL-5 transgenic (IL5Tg) mouse, we have first established an experimental model of liver injury caused by activated eosinophils.lL5Tg mice (C3H/HeN-TgN(IL-5)Imeq) have been established and provided from DR.Tominaga, Kochi Medical School. Although this mouse exhibits marked eosinophilia (30-70%) in the periphery, tissue injuries are not observed in any organs. IL5Tg mice were injected with 25 mug of LPS (Salmonella minesota Re 595) interaperitoneally and sacrificed 2 weeks later. Histological examinations showed marked portal inflammation with eosinophilic infiltrations (>50%) in portal tracts and extensive lobutar necrosis surround … More by marked eosinophils. Some small bile ducts were degenerated and destructed with eosinophihic aggregates, where eositiophilic infiltrations into ductal epithelium were observed. Electron microscopic examinations showed degranulation of eosinophilic cytotoxic granules into the ductal cells. Tissue injuries other than liver were almost absent in IL5Tg mice. in control mice (C3H/HeN), LPS injection did not induced any tissue injuries.Spleen cells (2x107 cells ; eosinophils>50%) from IL5Tg primed with LPS were transferred into none-transgenic mice (C3H/HeN) intravenously, but any tissue injuries were never induced. This result suggests that in addition to activated eosinophils, another factors such as various cytokines including TNF a released from LPS stimulated Kupffer cells are necessary for the induction of eosinophilic hepatic injury. Further analysis for dynamic changes of cytokines or chemokines, which are related to chemotaxis and degranulation of activated eosinophils, is needed for understanding the hepatic injury in this animal model. Less