Department of Surgery, The Warren Alpert Medical School of Brown University, Hasbro Children's Hospital, Room 147, 593 Eddy Street, Providence, RI 02903, USA.
Am J Pathol. 2010 Mar;176(3):1271-81. doi: 10.2353/ajpath.2010.090527. Epub 2010 Jan 28.
Biliary obstruction results in a well-characterized cholestatic inflammatory and fibrogenic process; however, the mechanisms and potential for liver repair remain unclear. We previously demonstrated that Kupffer cell depletion reduces polymorphonuclear cell (neutrophil) (PMN) and matrix metalloproteinase (MMP)8 levels in repairing liver. We therefore hypothesized that PMN-dependent MMP activity is essential for successful repair. Male Sprague-Dawley rats received reversible biliary obstruction for 7 days, and the rat PMN-specific antibody RP3 was administered 2 days before biliary decompression (repair) and continued daily until necropsy, when liver underwent morphometric analysis, immunohistochemistry, quantitative RT-PCR, and in situ zymography. We found that RP3 treatment did not reduce Kupffer cell or monocyte number but significantly reduced PMN number at the time of decompression and 2 days after repair. RP3 treatment also blocked resorption of type I collagen. In addition, biliary obstruction resulted in increased expression of MMP3, MMP8, and tissue inhibitor of metalloproteinase 1. Two days after biliary decompression, both MMP3 and tissue inhibitor of metalloproteinase 1 expression declined toward sham levels, whereas MMP8 expression remained elevated and was identified in bile duct epithelial cells by immunohistochemistry. PMN depletion did not alter the hepatic expression of these genes. Conversely, collagen-based in situ zymography demonstrated markedly diminished collagenase activity following PMN depletion. We conclude that PMNs are essential for collagenase activity and collagen resorption during liver repair, and speculate that PMN-derived MMP8 or PMN-mediated activation of intrinsic hepatic MMPs are responsible for successful liver repair.
胆道阻塞可导致特征明显的胆汁淤积性炎症和纤维发生过程；然而，肝脏修复的机制和潜力仍不清楚。我们之前的研究表明，枯否细胞耗竭可降低修复肝脏中多形核细胞（中性粒细胞）（PMN）和基质金属蛋白酶（MMP）8 的水平。因此，我们假设PMN 依赖性 MMP 活性对于成功修复是必需的。雄性 Sprague-Dawley 大鼠接受为期 7 天的可逆性胆道阻塞，在胆道减压（修复）前 2 天给予大鼠 PMN 特异性抗体 RP3，并持续每日给药直至尸检，此时对肝脏进行形态计量学分析、免疫组织化学、定量 RT-PCR 和原位酶谱分析。我们发现，RP3 治疗并未减少枯否细胞或单核细胞数量，但在减压时和修复后 2 天明显减少了 PMN 数量。RP3 治疗还阻断了 I 型胶原的吸收。此外，胆道阻塞导致 MMP3、MMP8 和金属蛋白酶组织抑制剂 1 的表达增加。胆道减压后 2 天，MMP3 和金属蛋白酶组织抑制剂 1 的表达均下降至 sham 水平，而 MMP8 的表达仍升高，并通过免疫组织化学在胆管上皮细胞中被鉴定。PMN 耗竭并未改变这些基因在肝脏中的表达。相反，基于胶原的原位酶谱显示，PMN 耗竭后胶原酶活性明显降低。我们得出结论，PMN 在肝脏修复过程中的胶原酶活性和胶原吸收中是必需的，并推测 PMN 衍生的 MMP8 或 PMN 介导的固有肝 MMP 激活是成功修复肝脏的原因。
