A method for preparing rat model of gut origin sepsis via hepatic portal vein injection

Abstract

Objective To establish a rat model of gut origin sepsis induced by portal vein injection. Methods Twelve rats of 84 SD rats (250~300 g, 12 weeks) were used for preparation of peritoneal exudate of gut derived sepsis by cecal ligation and perforation (CLP). The other 72 rats were randomly divided into portal vein sham group (PV-S), portal vein exudate group (PV-E) and vena cava exudate group (VC-E), 24 rats in each group. Normal saline for 1 ml was injected into hepatic portal vein in PV-S group rats. The same amount of peritoneal exudate of gut origin sepsis was injected into rat body in PV-E group and VC-E group through the hepatic portal vein and inferior vena cava. Each group was divided into four subgroups according to intraperitoneal injection at 1, 2, 4 and 6 h. The abdominal aorta blood of subgroup was collected on different time points. The rats were executed and bronchoalveolar lavage fluid (BALF) was collected to detect the volume of endotoxin, tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in serum and BALF, calculate the wet/dry weight ratio (W/D) and observe morphological and pathological changes of the lung. Results Concentrations of endotoxin, TNF-α, and IL-6 and lung pathology score and lung W/D of PV-E group rat were significantly higher than those of PV-S groupafter peritoneal exudate injection 1, 2, 4, 6 h (P<0.05). Compared to PV-E group, the levels of endotoxin in VC-E group rats were increased and TNF-αand IL-6 in serum and BALF were decreased after peritoneal exudate injection 1, 2, 4, 6 h (P<0.05). Compared with PV-S group, the rats showed pulmonary edema, extensive and patchy hemorrhage and congestion in PV-E group. The W/D in PV-E group(1 h: 8. 53±2.05, 2 h: 9.41±1.24, 4 h: 10.35±0.69, 6 h: 11.05±1.95) was higher than that of PV-S group (1 h: 5.16±1.13, 2 h: 5.17±1.34, 4 h: 5.14±2.04, 6 h: 5.13±1.95) and VC-E group (1 h: 6.71±0.73, 2 h: 7.65±1.32, 4 h: 8.40±0.43, 6 h: 9.41±1.87, P<0.05). The degree of lung injury in group VC-E was lighter than that of PV-E group. Pulmonary histology showed a large number of neutrophils and monocytes, and even red blood cell infiltration, severe alveolar wall destruction and pulmonary interstitial edema in the PV-E group rats, and the histological score in PV-E group was higher than that in PV-S group (1 h: 5.32±1.35 vs 0.25±0.02. 2 h: 6.44±0.72 vs 0.23±0.04. 4 h: 7.52±1.45 vs 0.27±0.02. 6 h: 8.69±0.35 vs 0.22±0.05, P<0.05) and VC-E group (1 h: 5.32±1.35 vs 3.37±0.73. 2 h: 6.44±0.72 vs 4.82±1.32. 4 h: 7.52±1.45 vs 6.47±0.43.6 h: 8.69±0.35 vs 8.4±1.87, P<0.05). Conclusions The CLP method can be used to prepare the intestinal derived peritoneal effusion. A rat model of intestinal origin sepsis is successfully established by the portal vein injecting intestinal derived peritoneal effusion. Key words: Gut origin sepsis; Cecal ligation and perforation; Portal vein injection; Lipopolysaccharide; Tumor necrosis factor-α; Interleukin-6