Harty Mark W, Papa Elaine F, Huddleston Hannah M, Young Ezekiel, Nazareth Samantha, Riley Charles A, Ramm Grant A, Gregory Stephen H, Tracy Thomas F
Department of Surgery, The Warren Alpert Medical School of Brown University and Hasbro Children's Hospitals, Providence, RI 02903, USA.
Surgery. 2008 May;143(5):667-78. doi: 10.1016/j.surg.2008.01.008.
Cholestatic liver injury from extrahepatic biliary obstruction is well characterized by inflammatory and fibrogenic mechanisms. Little is known, however, about mechanisms required to reverse injury and effect liver repair. We sought to determine the cellular and molecular requirements for repair after biliary decompression, focusing on the role of hepatic macrophages in regulating inflammation and matrix resolution.
Male Sprague-Dawley rats underwent bile duct obstruction for 7 days followed by ductular decompression. Rats were treated with gadolinium chloride (GdCl(3)) to deplete the macrophage populations 24 or 48 hours before decompression. Liver tissue obtained at the time of decompression or after 2 days of repair was processed for morphometric analysis, immunohistochemistry, quantitative RT-PCR and in situ hybridization.
GdCl(3) treatment for either 24 or 48 hours before decompression reduced the numbers of ED2(+) Kupffer cells and ED1(+) inflammatory macrophages in obstructed livers; only 48 hours of pretreatment, however, reduced the neutrophil counts. Furthermore, 48-hour GdCl(3) pretreatment blocked matrix degradation. Quantitative polymerase chain reaction demonstrated decreased cytokine-induced neutrophil chemoattractant-1 (CINC-1; CXCL1) and intercellular adhesion molecule-1 mRNA expression after GdCl(3) treatment and the elimination of hepatic macrophages. Immunohistochemistry and in situ hybridization revealed that neutrophils and CINC-1 mRNA localize within regions of fibrotic activity during both injury and repair.
We conclude that the macrophage population is not directly involved in fibrotic liver repair. Rather, hepatic macrophages regulate the influx of neutrophils, which may play a direct role in matrix degradation.
肝外胆管梗阻所致胆汁淤积性肝损伤的炎症和纤维化机制已得到充分阐明。然而，对于逆转损伤和实现肝脏修复所需的机制却知之甚少。我们试图确定胆管减压后修复的细胞和分子需求，重点关注肝巨噬细胞在调节炎症和基质溶解中的作用。
雄性Sprague-Dawley大鼠胆管梗阻7天，随后进行胆管减压。在减压前24或48小时，用氯化钆（GdCl₃）处理大鼠以耗尽巨噬细胞群体。在减压时或修复2天后获取肝脏组织，进行形态计量分析、免疫组织化学、定量逆转录聚合酶链反应和原位杂交。
减压前24或48小时给予GdCl₃处理可减少梗阻肝脏中ED2⁺库普弗细胞和ED1⁺炎性巨噬细胞的数量；然而，只有预处理48小时才能减少中性粒细胞计数。此外，48小时的GdCl₃预处理可阻断基质降解。定量聚合酶链反应显示，GdCl₃处理和清除肝巨噬细胞后，细胞因子诱导的中性粒细胞趋化因子-1（CINC-1；CXCL1）和细胞间黏附分子-1的mRNA表达降低。免疫组织化学和原位杂交显示，在损伤和修复过程中，中性粒细胞和CINC-1 mRNA定位于纤维化活动区域。
我们得出结论，巨噬细胞群体不直接参与纤维化肝脏的修复。相反，肝巨噬细胞调节中性粒细胞的流入，而中性粒细胞可能在基质降解中起直接作用。
