[Recombinant polypeptide of N-terminal heparin-binding domain of fibronectin antagonizes hepatic failure induced by endotoxin in mice].

OBJECTIVE

To study the preventive effect of recombinant polypeptide of N-terminal heparin-binding domain of fibronectin on hepatic failure induced by endotoxin in mice.

METHODS

The 40 hepatic failure Balb/C mice were established by intraperitoneal injection of lipopolysaccharide (LPS) and d-galactosamine (GalN). The mice were randomly divided into two groups, one for polypeptide treatment, the othe for saline treatment.Another 20 mice were used as normal control. Half hour prior to, 1, 2, and 3 hours after injection of LPS and GalN, the rhFNHN-29 polypeptide (10 mg/kg) was injected through the tail vein of mice. The same volume of saline was given to the saline treated group and the normal control group.Six hours after the injection of LPS and GalN, 250 microl blood was taken from the eye vein of each mouse for plasma TNFalpha testing, and 72 hours after the injection, mortality rates of the mice of different groups were observated. The liver, lung, heart, kidney, and brain tissues of the survival mice were examined for histopathology after 72 hours. The Liver tissue was also examined for electron micrograph and for mRNA expression of TNFalpha, IL-1beta, IL-6 by RT-PCR.

RESULTS

The 72 hours mortality rates in saline-treated and polypeptide treated-mice were 70% and 15% respectively (P < 0.01). The histopathology showed that necrosis occurred less on the hepatocytes of polypeptide treated mice than on the saline treated ones. The ultrastructure of hepatocyte under the electron microscope showed that cell apparatus of saline treated mice were destroyed and cytoplasm become loose. The expression level of TNFalpha, IL-1beta, IL-6 mRNA on hepatocytes in polypeptide treated mice was significantly lower (1.26 +/- 0.37, 0.98 +/- 0.21, 0.43 +/- 0.17, 87.43 +/- 16.7 respectively) than that in the saline treated ones (1.98 +/- 0.56, 1.24 +/- 0.35, 0.64 +/- 0.25 and 236.11 +/- 32.7, respectively) (P < 0.01). Similarly, the plasm TNFalpha level (87.43 +/- 16.7) in polypeptide treated group was significantly lower than that (236.11 +/- 32.7) in the saline treated group (P < 0.01).

CONCLUSION

The rhFNHN-29 polypeptide can prevent and treat hepatic failure induced by endotoxin. The mechanism by which the polypeptide takes the effect may involve its ability to down-regulate expression of those inflammation factors such as TNFalpha, IL-1beta, IL-6.