Correlative study of ulinastatin in the treatment of rats with septic acute liver injury via p38 mitogen-activated protein kinase pathway

Abstract

Objective 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. Methods 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. Results 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 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), 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. Conclusions 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. Key words: Sepsis; Acute liver injury; Lipopolysaccharide; Ulinastatin; p38MAPK pathway; Tumor necrosis factor-α