Effects of recombinant human TNFR: Fc fusion protein on rat acute liver injury induced by lipopolysaccharide

Abstract

Objective To investigate the protective effects and the undedying mechanism of recombinant human tumor necrosis factor receptor: Fc fusion protein (Yisaipu, rhu TNFR: Fc) on the lipopolysaccharide (LPS) induced acute liver injury of rats. Method Totally48 SD rats were randondy divided into four groups , in-cluding control gronp (n = 12), Yisaipu group(n = 12), LPS gronp(n = 12) and Yisaipu + IPS group(n = 12). The models of acute liver injury were produced by injection of LPS intravenously. Being fasted for 12 h, the rats were anaesthetized (60 mg/kg pentobarbital sodium, i.p.) and cannulated into carotid arteries. The cannula was connected with the multi-channel creature signal analysis system. The rata in control group and LPS group were injected with normal saline or LPS in dose of 5 mg/kg through rats' sublingual vein respectively. While the rats in Yisaipu group and Yisaipu + LPS group was pretreated with Yisaipu in dose of 0.4 mg/kg subcutaneously 24 h be-fore normal saline or LPS infusion. Six rats of each goup were randomly selected and mean arterial pressure (MAP) were monitored for 6 h via multi-channel creature signal analysis system, and rats' survival rate was calcu-lated. The rats whose MAP less than 10 mmHg were considered to die and the alive rats during period of observa-tion sacrificed by exsanguination. The liver tissue at the same site was removed, fixing in 10% formalin or stored at -80 ℃. To detect serum TNF-α, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level, 0.2 mL blood samples were collected from the carotid artery 2 and 3 h after the injection of saline or LPS. The serum was collected from centrifuged blood samples and stored at -80 ℃. Enzyme-linked immunosorbent assay (ELISA) and flow cytometry were used to assess serum TNF-α level and bioactivity respectively. We also measured the serum ALT and AST levels, the myeloperoxiase (MPO) and superexide dismutase (SOD) activity, and malon-dialdehyde (MDA) content in liver tissue The pathology of hepatic tissue was evaluated by HE staining. Statistical-ly,the data of TNF-α level and bioactivity, ALT and AST release, and MDA content were analyzed by ANOVA, and rat survival rate were analyzed by Chi-square Tests. Results The rats in control group and Yisaipu group were all survived. Rat survival rate was significantly higher in Yisaipu + LPS group (67%) than in LPS group (17%) (P < 0.05). Serum TNF-α bioactivity was significantly lower in Yisaipu + LPS group than in LPS group [(7.3±2.8)% vs.(51.3±6.4)%, P <0.05]. Compared with IPS group, Yisaipu pretreatment decreased MDA content [(1.40±0.10)vs. (2.81±0.11) nmol/mgprot, P <0.05]and MPO acticity [(0.38±0.04) vs. (0.54±0.02) U/g, P <0.05]in hepatic tissue, while SOD activity [(188.4±20.2) vs. (142.5 ± 18.3) U/mgprot, P <0.05]was increased. The serum AST level, ALT level and the pathology in the liver were also ameliorated correspondingly. Conclusions These data suggest that Yisaipu could protect rats from LPsinduced a-cute liver injury by inhibiting TNF-α bioactivity and by enhancing anti-oxidation. Key words: Yisaipu; Tumor necrosis factor-α; Lipopolysaccharide; Acute liver injury