Tolba René H, Fet Ngwi, Yonezawa Kei, Taura Kojiro, Nakajima Akio, Hata Koichiro, Okamura Yusuke, Uchinami Hiroshi, Klinge Uwe, Minor Thomas, Yamaoka Yoshio, Yamamoto Yuzo
Division of Surgical Research, University Hospital Bonn, Bonn, Germany.
Eur Surg Res. 2014;53(1-4):11-24. doi: 10.1159/000362411. Epub 2014 May 14.
Ischemia/reperfusion injury (IRI) is one of the major clinical problems in liver and transplant surgery. Livers subjected to warm ischemia in vivo often show a severe dysfunction and the release of numerous inflammatory cytokines and arachidonic acid metabolites. Cyclooxygenase (COX)-2 is the inducible isoform of an intracellular enzyme that converts arachidonic acid into prostaglandins. The aim of the study was to evaluate the effect of COX-2 inhibition and the role of Kupffer cells in IRI of the liver.
Male Wistar rats [250- 280 g body weight (BW)] were anesthetized and subjected to 30-min warm ischemia of the liver (Pringle's maneuver) and 60-min reperfusion after median laparotomy. The I/R group received no additional treatment. In the COX-2 inhibitor (COX-2I) group, the animals received 1 mg/kg BW meloxicam prior to operation. Gadolinium chloride (GdCl3) (10 mg/kg BW) was given 24 h prior to operation in the GdCl3 and GdCl3 + COX-2I groups for the selective depletion of Kupffer cells. The GdCl3 + COX-2I group received both GdCl3 and meloxicam treatment prior to operation. Blood and liver samples were obtained at the end of the experiments for further investigations.
After 30 min of warm ischemia in vivo, severe hepatocellular damage was observed in the I/R group. These impairments could be significantly prevented by the selective COX-2 inhibition and the depletion of Kupffer cells. Alanine aminotransferase was significantly reduced upon meloxicam and GdCl3 treatment compared to the I/R group: I/R, 3,240 ± 1,262 U/l versus COX-2I, 973 ± 649 U/l, p < 0.001; I/R versus GdCl3, 1,611 ± 600 U/l, p < 0.05, and I/R versus GdCl3 + COX-2I, 1,511 ± 575 U/l, p < 0.01. Plasma levels of tumor necrosis factor alpha (TNF-α) were significantly reduced in the COX-2I treatment group compared to I/R (3.5 ± 1.5 vs. 16.3 ± 11.7 pg/ml, respectively; p < 0.05). Similarly, the amount of TxB2, a marker for COX-2 metabolism, was significantly reduced in the meloxicam treatment groups compared to the I/R group: I/R, 22,500 ± 5,210 pg/ml versus COX-2I, 1,822 ± 938 pg/ml, p < 0.001, and I/R versus GdCl3 + COX-2I, 1,530 ± 907 pg/ml, p < 0.001. All values are given as mean ± SD (n = 6).
These results suggest that the inhibition of COX-2 suppressed the initiation of an inflammatory cascade by attenuating the release of TNF-α, which is an initiator of the inflammatory reaction in hepatic IRI. Therefore, we conclude that preferential inhibition of COX-2 is a possible therapeutic approach against warm IRI of the liver.
缺血/再灌注损伤（IRI）是肝脏和移植手术中的主要临床问题之一。体内经历热缺血的肝脏常表现出严重功能障碍，并释放大量炎性细胞因子和花生四烯酸代谢产物。环氧化酶（COX）-2是一种将花生四烯酸转化为前列腺素的细胞内酶的诱导型同工酶。本研究的目的是评估COX-2抑制的作用以及库普弗细胞在肝脏IRI中的作用。
雄性Wistar大鼠[体重（BW）250 - 280 g]经麻醉后，在正中剖腹术后进行30分钟肝脏热缺血（普林格尔手法）和60分钟再灌注。IRI组未接受额外治疗。在COX-2抑制剂（COX-2I）组中，动物在手术前接受1 mg/kg BW的美洛昔康。在GdCl3组和GdCl3 + COX-2I组中，于手术前24小时给予氯化钆（GdCl3）（10 mg/kg BW）以选择性清除库普弗细胞。GdCl3 + COX-2I组在手术前接受GdCl3和美洛昔康治疗。实验结束时采集血液和肝脏样本用于进一步研究。
在体内进行30分钟热缺血后，IRI组观察到严重的肝细胞损伤。这些损伤可通过选择性COX-2抑制和库普弗细胞清除得到显著预防。与IRI组相比，美洛昔康和GdCl3治疗后丙氨酸转氨酶显著降低：IRI组为3240 ± 1262 U/l，COX-2I组为973 ± 649 U/l，p < 0.001；IRI组与GdCl3组相比为1611 ± 600 U/l，p < 0.05，IRI组与GdCl3 + COX-2I组相比为1511 ± 575 U/l，p < 0.01。与IRI组相比，COX-2I治疗组血浆肿瘤坏死因子α（TNF-α）水平显著降低（分别为3.5 ± 1.5与16.3 ± 11.7 pg/ml；p < 0.05）。同样，作为COX-2代谢标志物的TxB2量，与IRI组相比，美洛昔康治疗组显著降低：IRI组为22500 ± 5210 pg/ml，COX-2I组为1822 ± 938 pg/ml，p < 0.001，IRI组与GdCl3 + COX-2I组相比为1530 ± 907 pg/ml，p < 0.001。所有数值均以平均值±标准差（n = 6）表示。
这些结果表明，COX-2抑制通过减弱TNF-α的释放抑制了炎症级联反应的启动，TNF-α是肝脏IRI中炎症反应的启动因子。因此，我们得出结论，优先抑制COX-2是治疗肝脏热IRI的一种可能的治疗方法。
