内毒素耐受对急性肝功能衰竭大鼠肝脏CXCR7表达的影响

The effect of endotoxin tolerance on the expression of chemokine receptor 7 in rats with the acutehepatic failure

目的通过研究内毒素耐受（endotoxin tolerance，ETT）对急性肝功能衰竭（acute liver failure，ALF）大鼠肝组织中趋化因子受体7（chemokine receptor7，CXCR7）表达变化的影响，探讨E1Tr发生的可能机制。方法雄性sD大鼠随机（随机数字法）分为健康对照组（N组）、急性肝功能衰竭组（ALF组）和内毒素耐受组（ETT组）。ErIT组和ALF组先分别以0．1mg／kg脂多糖（1ipopoIysaccharide，LPS）和生理盐水腹腔注射，每日1次，于第5次注射24h后同时腹腔注射D-氨基半乳糖（D—galactosamine，D-GalN）（800mg／kg）和LPS（8μg/只），分别在注射后2、6、12、24、48h时间点留取大鼠血及肝脏标本。RT—PCR法检测肝组织中CXCR7mRNA表达；Westernblot法检测CXCR7蛋白表达。统计处理采用LSD检验、Dunnet’st检验。结果E，兀’组大鼠肝组织病理改变较ALF组明显减轻；ETT组肝组织CXCR7mRNA表达水平虽高于正常组，但却明显低于ALF组，与ALF组比较，差异均具有统计学意义（2、6、12、24、48h时间点比较，F值分别为29．222、166．892、38．975、34．603、18．929，均P〈0．01）。ETT组、ALF组CXCR7蛋白的表达24h时均达峰值，但ETT、组CXCR7蛋白的表达较ALF组明显下降（2、6、12h时的F值分别为11．155、42．553、17．082，均P〈0．ol；24h时的F值7．242，P〈0．05）。结论内毒素耐受时，大剂量LPS和D—GalN能减轻肝脏损害，明显下调CXCR7mRNA和CXCR7蛋白表达，提示CXCR7在内毒素耐受的形成机制中可能发挥重要作用。

Objective To study the effect of endotoxin tolerance （ETr） on chemokine receptor 7 （ CXCR7 ） in the liver tissue of rats with acute liver failure （ALF）. Methods SD male rats were randomly divided into three groups： normal group, ALF group and ETT group. The rats in the ETr group and ALF group were injected with lipopolysacharide （LPS） 0. 1 mg/kg or saline respectively, one time / day for 5 days. At 24 hours after the 5th - day injection, all rats were injected with D-GaiN 800 mg/kg and LPS 8txg/ rat. Blood sample and liver tissue were collected on 2, 6, 12, 24 and 48 hours after injection. The gene expressions of CXCR7 in the liver were measured by RT-PCR, and the protein expressions of CXCR7 were determined by Western Blot. The data analysis was performed by LSD, Dunnett＇ s t test. Results The histological damage in the liver tissue was significantly mider in ETr group compared to ALF group. The gene expressions of CXCR7 were significantly milder in ETT group compared to ALF group （2 h： F = 29. 222, 6h： F=166.892, 12h： F=38.975, 24h： F=34.603,48h： F=18.929, allP〈0.01）, but still severer than that of normal group. The CXCR7 protein expression in ALF group and ETF grouppeaked at 24 hours, but the expression of CXCR7 in ETT group was lower compared with that in in ALF group （2h： F=11.155, 6h： F=42.553, 12 h： F=17.082, all P〈0.01; 24h： F=7.242, P〈 0. 05）. Conclusions During the process of endotoxin tolerance, LPS pretreatment and D-GaIN can decrease the liver injury, down -regulate the expressions of CXCR7mRNA and CXCR7. This suggests that CXCR7 may play an important role in the ETT.