[The dose-dependent protective effect of curcumin on hepatocyte of rats with sepsis]

To observe the protective effect of different doses of curcumin on hepatocytes of rats with sepsis.

100 healthy male Sprague-Dawley (SD) rats were randomly divided into sham operation group, sepsis group, and low, medium, high dose curcumin intervention groups (L-cur, M-cur, H-cur groups), with 20 rats in each group. The animal model of sepsis was reproduced by cecal ligation and puncture (CLP) method, and in the sham operation group the cecum was just taken out and returned. In the L-cur, M-cur, H-cur groups curcumin was immediately injected after CLP with a dose of 50, 100, 150 mg/kg, respectively, and the rats in sham operation group and sepsis group were given the same amount of normal saline. Five rats in each group were sacrificed at 2, 6, 12, 24 hours after operation, and the hepatic tissues and blood samples were obtained. The pathological changes in hepatic tissues were observed under a microscope, and hepatocytes apoptosis and apoptosis index (AI) of hepatocytes were determined with transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) method, and the levels of serum procalcitonin (PCT), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were determined with enzyme linked immunosorbent assay (ELISA) method.

Microscopic examination showed that the damage degree of hepatic tissues was significantly increased in sepsis group; the number of apoptotic cells and damage degree of hepatic tissues were increased gradually over time. The damage degree of hepatic tissues in curcumin groups was lessened as compared with sepsis group, especially in M-cur group. There were no significant changes in AI and serum PCT, TNF-α, and IL-1β levels at any of the time points tested in the sham operation group. The AI, serum PCT, TNF-α, and IL-1β levels in the sepsis group were significantly higher than those in the sham operation group from 2 hours after operation on [AI: (23.59±2.00)% vs. (2.02±0.13)%, PCT (μg/L): 2.41±0.21 vs. 0.81±0.01, TNF-α (ng/L): 217.28±14.24 vs. 80.02±2.26, IL-1β (ng/L): 61.84±3.21 vs. 25.78±1.29, all P < 0.05], and they showed a gradually increasing tendency. AI reached peak value at 24 hours after operation [(52.05±1.31)%]; PCT, TNF-α and IL-1β reached the peak values at 12 hours after operation [(8.68±0.58) μg/L, (314.13±14.39) ng/L, (132.24±2.58) ng/L, respectively]. Curcumin intervention significantly reduced the levels of AI, TNF-α, PCT and IL-1β in hepatocytes of septic rats, especially in M-cur group [AI: (11.56±0.96)% vs. (23.59±2.00)% at 2 hours, (30.35±1.20)% vs. (52.05±1.31)% at 24 hours; PCT (μg/L): 1.13±0.19 vs. 2.41±0.21 at 2 hours, 5.09±0.42 vs. 8.68±0.58 at 12 hours; TNF-α (ng/L): 124.73±7.47 vs. 217.28±14.24 at 2 hours, 168.68±6.95 vs. 314.13±14.39 at 12 hours; IL-1β (ng/L): 35.05±1.00 vs. 61.84±3.21 at 2 hours, 84.06±3.42 vs. 132.24±2.58 at 12 hours; all P < 0.05].

Curcumin can inhibit the inflammatory reaction of hepatocytes of rats, prevent apoptosis, and protect the hepatocytes of rats with sepsis. The concentration of curcumin with the most significant effect is 100 mg/kg, which is the medium dosage.