氯屈膦酸二钠-超顺磁性氧化铁脂质体减轻重症急性胰腺炎肾损伤

研究目的：探讨氯属膦酸二钠-超顺磁性氧化铁（SPIO）脂质体对重症急性胰腺炎（SAP）肾损伤的保护作用。创新要点：围绕SAP并发多器官损伤这一核心问题，联系巨噬细胞在SAP发病过程中的作用，使用纳米脂质体携带氯屈膦酸二钠及SPIO，以及利用自体巨噬细胞对SAP时多器官损伤的定性靶向性以及磁性纳米颗粒的超顺磁性，应用磁共振成像（MRI）对SAP并发多器官损伤进行早期诊断。结合使用氯屈膦酸二钠，使其促进巨噬细胞的凋亡，减少其在急性胰腺炎早期产生炎症介质，阻止全身性炎症反应的进程，从而实现对多器官损伤的保护作用。研究方法：采用胰腺被膜下均匀注射5％牛磺胆酸钠制作SAP模型。SD大鼠48只，随机分为对照组（C组）、空白SPIO脂质休组（P组）和氯屈膦酸二钠＋SPIO脂质体组（T组）。P组和T组大鼠制作SAP模型。制模2h和6h后取肠系膜上静脉血液，检测各组大鼠血清中淀粉酶、尿素氮、血肌酐和肿瘤坏死因子-α的含量，观察胰腺及肾组织的病理学变化及进行病理评分，通过检测肾组织的TUNEL染色及CD68表达研究氯属膦酸二钠-超顺磁性氧化铁脂质体对肾组织巨噬细胞凋亡的影响并进行MRI诊断。重要结论：氯屈膦酸二钠-超顺磁性氧化铁脂质体可选择性清除单核／巨噬细胞，减少炎症介质释放，对SAP大鼠胰腺及肾损伤有保护作用。SPIO可作为MRI示踪。

Clodronate-superparamagnetic iron oxide-containing liposomes attenuate renal injury in rats with severe acute pancreatitis

Background and objective： It has been shown that macrophages play an important role in the development of severe acute pancreatitis （SAP）, and eventually lead to multiple organ failure （MOF）. Clodronate-liposome selectively depleted macrophages. This study was to investigate the role of renal macrophage infiltration in acute renal injury in rats with SAP and to evaluate the potential of superparamagnetic iron oxide （SPIO）-enhanced magnetic resonance imaging （MRI） for diagnosis. Methods： Superparamagnetic Fe3O4 nanoparticles were prepared by chemical coprecipitation. SPIO-liposomes and SPIO-clodronate-liposomes were prepared by the thin film method. SAP models were prepared by injection of sodium taurocholate into the subcapsular space of rat pancreas. Sprague-Dawley rats were randomly divided into a control group, SAP plus SPIO-liposome （P） group, and SAP plus SPIO-clodronatecontaining liposome （T） group. Kidney injury was evaluated by T2-weighted MRI scan. The levels of serum amylase （SAM）, blood urea nitrogen （BUN）, and serum creatinine （SCr） were measured by an automated enzymatic method. Serum tumor necrosis factor-α （TNF-α） was measured by enzyme-linked immunosorbent assay （ELISA）. Pathological changes in the pancreas and kidney were observed using hematoxylin and eosin （H＆E） staining, while cell apoptosis was detected with terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL） staining. In addition, the macrophage markers （CD68） of the renal tissue were detected with immunohistochemistry. Results： The pathological changes in the pancreas and kidneys of rats in the T group were milder than those in the P group. The MRI signal intensity of the kidneys in the P and T groups was significantly lower than that in the control group. There were significant changes in the two experimental groups （P〈0.01）. The levels of SAM, Bun, SCr, and TNF-α in rats in the P group were higher than those in the control group （P〈0.01） and in the T group （P〈0.01）. The apoptosis of the kidney in the T group was higher than that in the P group at 2 and 6 h （P〈0.01）. Conclusions： Clodronate-containing liposomes protected against renal injury in SAP rats, and SPIO can be used as a tracer for MRI examination to detect renal injury in SAP rats. SPIO-aided MRI provided an efficient non-invasive way to monitor the migration of macrophages after renal injury in rats with SAP.