探讨乌司他丁对脂多糖（LPS）诱导的大鼠脓毒症急性肝损伤的治疗作用及相关机制，并与p38丝裂原活化蛋白激酶（MAPK）通路特异性阻断剂SB203580的疗效进行比较。

通过尾静脉注射5 mg/kg的LPS制造LPS诱导的大鼠脓毒症急性肝损伤模型。将清洁级雄性Sprague-Dawley大鼠32只分为4组：空白组（尾静脉注射1 mL等渗NaCl溶液），LPS组（尾静脉注射1 mL的LPS），LPS +乌司他丁（UTI）组（建模后立即腹腔注射1 mL乌司他丁），LPS + p38MAPK通道阻断剂（SB）组（建模后立即腹腔注射1 mL SB203580），每组8只。建模后24 h处死大鼠，取下腔静脉血测定大鼠血清中谷氨酸-丙酮酸转氨酶（ALT）、胆红素（BIL）和碱性磷酸酶（AKP）的浓度，利用酶联免疫吸附测定（ELISA）法检测大鼠肝组织肿瘤坏死因子α（TNF-α）水平，Western-blotting法测定大鼠肝组织磷酸化p38蛋白水平表达，以及通过肝组织病理切片和电镜下观察肝细胞微结构的变化。

建模后24 h，LPS组有2只大鼠死亡。四组大鼠血清AKP水平无显著性差异（F = 1.153，P = 0.351）；与空白组比较，LPS组大鼠血清ALT [（10.7 ± 1.8）U/L vs.（46.3 ± 5.0）U/L]、BIL[（0.63 ± 0.12）μmol/L vs.（1.55 ± 0.16）μmol/L]、肝组织TNF-α[（4 621 ± 793）ng/L vs.（7 222 ± 773）ng/L]、磷酸化p38蛋白水平[（12 073 ± 172）ng/L vs.（15 515 ± 630）ng/L]均显著升高（P均< 0.05）；病理切片提示LPS组肝细胞水样变性、炎症细胞浸润、肝细胞再生；电镜结果也提示肝细胞核固缩，线粒体嵴肿胀、断裂或者消失，内质网结构不清。而LPS + UTI组和LPS + SB组肝组织TNF-α、磷酸化p38蛋白表达均与空白组无显著差异（P均> 0.05）；病理切片提示两组肝细胞水样变性、炎症细胞浸润、肝细胞再生较LPS组轻，但较空白组仍严重；电镜结果显示肝细胞核、线粒体及内质网结构变化较LPS组减轻。与空白组相比，LPS + SB组血清ALT无显著差异（P > 0.05），而LPS + UTI组血清ALT明显升高[（10.7 ± 1.8）U/L vs.（29.5 ± 2.5）U/L，P < 0.05]，提示SB203580对血清ALT作用更明显；而与空白组比较，LPS + UTI组血清BIL水平无显著差异（P > 0.05），而LPS + SB组血清BIL明显升高[（0.63 ± 0.12）μmol/L vs.（1.52 ± 0.20）μmol/L，P < 0.05]，提示乌司他丁对血清BIL作用更明显。

乌司他丁可减轻LPS引起的大鼠脓毒症急性肝损伤，是通过p38MAPK通路来发挥炎症抑制作用的。与p38MAPK通路特异性阻断剂比较，两者在减轻TNF-α、磷酸化p38蛋白等作用上相似，但是对血清学指标的影响有一定差别。

To investigate the therapeutic effect and related mechanism of ulinastatin on acute liver injury induced by lipopolysaccharide (LPS) in rats with sepsis, and compare with the therapeutic effect of p38 mitogen-activated protein kinase (MAPK) pathway specific blocker SB203580.

A rat model of LPS-induced septic acute liver injury was established by tail intravenous injection of 5 mg/kg LPS. Thirty-two pathogen-free male Sprague-Dawley rats were randomly divided into four groups: the blank group (tail intravenous injection of 1 mL isotonic NaCl solution), the LPS group (tail intravenous injection of 1 mL LPS), the LPS + ulinastatin (UTI) group (intraperitoneal injection of 1 mL ulinastatin immediately after model establishment) and the LPS + p38MAPK pathway blocker (SB) group (intraperitoneal injection of 1 mL SB203580 immediately after model establishment), 8 rats in each group. The rats were sacrificed 24 h after model establishment, and inferior caval venous blood was drawn to detect the levels of alanine transaminase (ALT), bilirubin (BIL) and alkaline phosphatase (AKP)s. The enzyme-linked immuno sorbent assay (ELISA) method was used to detecte the level of tumor necrosis factor alpha (TNF-α) in the liver tissue. The expression of phosphorylated p38 protein in liver tissue was determined by Western-blotting. The changes in the microstructure of hepatocytes were observed by pathological section of liver tissue and electron microscope.

Two rats died in the LPS group 24 h after model establishment. There was no significant difference in serum AKP levels among the four groups (F = 1.153, P = 0.351); compared with the blank group, the levels of serum ALT [(10.7 ± 1.8) U/L vs. (46.3 ± 5.0) U/L], BIL [(0.63 ± 0.12) μmol/L vs. (1.55 ± 0.16) μmol/L], TNF-α [(4 621 ± 793) ng/L vs. (7 222 ± 773) ng/L] and phosphorylated p38 protein [(12 073 ± 172) ng/L vs. (15 515 ± 630) ng/L] in the LPS group were significantly higher (all P < 0.05). Pathological sections showed the hydropic degeneration, inflammatory cell infiltration, cell regeneration of liver cells in the LPS group; electron microscopy also prompted the hepatocyte nuclear condensation, the swelling, fracture or disappearance of mitochondrial crista, and the unclear endoplasmic reticulum structure. The levels of TNF-α and phosphorylated p38 protein in both LPS + UTI and LPS + SB groups showed no significant difference with those in the blank group (all P > 0.05). Pathological sections showed that the hydropic degeneration, inflammatory cell infiltration, cell regeneration of liver cells in LPS + UTI and LPS + SB groups were more relieved than those in the LPS group, but more serious than those in the blank group; electron microscopy also showed the changes of nuclear, mitochondria and endoplasmic reticulum in liver tissue in two groups were more relieved than those in the LPS group. Compared with the blank group, the level of serum ALT in the LPS + SB group showed no significant difference (P > 0.05), while the serum ALT in the LPS + UTI group was much higher [(10.7 ± 1.8) U/L vs. (29.5 ± 2.5) U/L, P < 0.05], which suggested that the effect of SB203580 in serum ALT was more obviously; conversely, compared with the blank group, the level of serum BIL in the LPS + UTI group showed no significant difference (P > 0.05), while the serum BIL in the LPS + SB group was much higher [(0.63 ± 0.12) μmol/L vs. (1.52 ± 0.20) μmol/L, P < 0.05], which suggested that the effect of ulinastatin in serum BIL was more obvious.

Ulinastatin can attenuate the acute liver injury induced by LPS in rats with sepsis, taking into account that ulinastatin played an inflammatory-inhibitor role through p38MAPK pathway. Compared with p38MAPK pathway specific blocker SB203580, the effects of inhibiting TNF-α and phosphorylated p38 protein expressions by ulinastatin were similar, but the effects of serological indexes had some differences.