IL-10 is involved in the protective effect of dibutyryl cyclic adenosine monophosphate on endotoxin-induced inflammatory liver injury

The effects of exogenous cAMP, dibutyryl cAMP (DBcAMP) on LPS-induced liver injury were examined in mice made hypersensitive to LPS by treatment with i.v. injection of Propionibacterium acnes. In vivo administration of DBcAMP significantly protected P. acnes-treated mice from LPS-induced liver injury, including apoptosis of hepatocytes. DBcAMP significantly increased circulating IL-10 level in correlation with suppression of the TNF-α level after LPS challenge in P. acnes-treated mice. Treatment with anti-IL-10 mAb abrogated the protective effect of DBcAMP on LPS-induced liver injury. Similar to in vivo findings, addition of DBcAMP to in vitro culture of liver adherent cells from P. acnes-treated mice enhanced IL-10 synthesis after LPS stimulation. These results suggest that the increment in IL-10 production by liver adherent cells is involved in the protective effect of DBcAMP on LPS- induced inflammatory liver injury.