Liver protection of crocetin against paraquat poisoning in rats / 中华危重病急救医学

ABSTRACT

Objective To study the liver protection of crocetin against paraquat (PQ) poisoning induced acute liver injury in rats. Methods Fifty-four male Wistar rats were randomly divided into control group, exposure group and treatment group, and the rats in each group were subdivided into the 0.5th, 2nd, and 6th day after exposure subgroups (n = 6). The model of acute liver failure induced by PQ poisoning was reproduced by intraperitoneal injection of 20 mg/kg of 20% PQ, and the rats in control group was injected with the same amount of normal saline. The rats in treatment group were given with intraperitoneal injection of 50 mg/kg crocetin after 0.5 day, once a day until they were sacrificed; the other two groups were injected with the same amount of normal saline. The rats in all groups were sacrificed at the corresponding time points, and blood was collected from inferior vena cava and hepatic tissue was harvested. Hematoxylin and eosin (HE) staining was used to observe the pathological changes in liver tissue on the 6th day under light microscope. Enzyme linked immunosorbent assay (ELISA) was used to detect the serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA expressions of inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB). The activities of apoptosis related factors, including caspase-8, -9, -12, in hepatic tissue were determined on the 6th day with chromogenic substrate method. Results In the liver tissue of exposed group, extensive infiltration of the inflammatory cells and the diffuse fragments necrosis were visible, and the regeneration of the liver cells was not obvious, and severity of the injury in a time dependent way. In the treatment group, the structure of hepatic artery was visible, and the infiltration of necrosis, congestion and inflammatory cells were not obvious. On the 0.5th, 2nd, and 6th day, serum levels of IL-6 and TNF-α, the mRNA expressions of iNOS and NF-κB in liver tissue, and the caspase-8, -9, -12 activities on the 6th day in the exposure group and treatment group were significantly higher than those in the control group. And the parameters in treatment group were significantly lower than those of the exposure group [IL-6 (ng/L) 188.37±64.21 vs. 376.61±82.42 on the 0.5th day, 287.18±58.69 vs. 432.77±96.28 on the 2nd day, 234.24±10.17 vs. 375.41±37.59 on the 6th day; TNF-α (ng/L) 472.36±76.43 vs. 688.33±102.19 on the 0.5th day, 189.32±87.54 vs. 296.21±89.77 on the 2nd day, 99.28±16.13 vs. 168.41±66.78 on the 6th day; iNOS mRNA (gray value) 2.998±0.801 vs. 3.453±0.026 on the 0.5th day, 3.126±0.306 vs. 5.259±0.153 on the 2nd day, 0.841±0.135 vs. 1.225±0.057 on the 6th day; NF-κB mRNA (gray value) 1.569±0.818 vs. 2.361±0.063 on the 0.5th day, 2.345±0.489 vs. 4.668±0.368 on the 2nd day, 2.348±0.316 vs. 3.972±0.449 on the 6th day; caspase-8 (pmol/mg) 126.77±9.97 vs. 199.18±66.48 on the 6th day; caspase-9 (pmol/mg) 213.12±69.06 vs. 321.62±89.39 on the 6th day; caspase-12 (pmol/mg) 183.46±70.52 vs. 219.68±53.93 on the 6th day, all P < 0.05]. Conclusion Crocetin has protective effect on liver in rats with PQ poisoning, which role is related with reducing the blood level of inflammatory factors, inhibiting the hepatic caspase-8, -9, -12 activities and gene expressions of iNOS and NF-κB.