Gene knockout or inhibition of macrophage migration inhibitory factor alleviates lipopolysaccharide-induced liver injury via inhibiting inflammatory response.

BACKGROUND

Liver injury is one of the most common complications during sepsis. Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine. This study explored the role of MIF in the lipopolysaccharide (LPS)-induced liver injury through genetically manipulated mouse strains.

METHODS

The model of LPS-induced liver injury was established in wild-type and Mif-knockout C57/BL6 mice. Serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBil) were detected, and the expressions of MIF, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured. Liver histopathology was conducted to assess liver injury. Moreover, the inhibitions of MIF with (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) and 4-iodo-6-phenylpyrimidine (4-IPP) were used to evaluate their therapeutic potential of liver injury.

RESULTS

Compared with wild-type mice, the liver function indices and inflammation factors presented no significant difference in the Mif mice. After 72 h of the LPS-induced liver injury, serum levels of ALT, AST, and TBil as well as TNF-α and IL-1β were significantly increased, but the knockout of Mif attenuated liver injury and inflammatory response. In liver tissue, mRNA levels of TNF-α, IL-1β and NF-κB p65 were remarkably elevated in LPS-induced liver injury, while the knockout of Mif reduced these levels. Moreover, in LPS-induced liver injury, the inhibitions of MIF with ISO-1 and 4-IPP alleviated liver injury and slightly attenuated inflammatory response. Importantly, compared to mice with LPS-induced liver injury, Mif knockout or MIF inhibitions significantly prolonged the survival of the mice.

CONCLUSIONS

In LPS-induced liver injury, the knockout of Mif or MIF inhibitions alleviated liver injury and slightly attenuated inflammatory response, thereby prolonged the survival of the mice. Targeting MIF may be an important strategy to protect the liver from injury during sepsis.