Histone preconditioning protects against obstructive jaundice-induced liver injury in rats

A major consequence of obstructive jaundice (OJ) in clinical practice is the development of severe liver injury, and at present, no effective treatments have been developed to protect against it. Preconditioning with damage-associated molecular pattern (DAMP) molecules has been demonstrated to protect multiple organs from injury, and histones have been recently identified as DAMP molecules. The aim of the present study was to investigate the protective effect of histone preconditioning against OJ-induced liver injury in rats and the involvement of Toll-like receptors. Rats were administered histone proteins (200 μg/kg; 1 ml) or physiological saline (1 ml) intraperitoneally 24 h prior to being subjected to bile duct ligation (BDL). The serum levels of liver enzymes and bilirubin, as well as the histopathology were analyzed. The mRNA expression of interleukin-6 (IL-6) in the liver tissue was analyzed using quantitative polymerase chain reaction. BDL in the control group caused severe OJ-induced liver injury, as indicated by the significantly elevated levels of liver enzymes and mRNA levels of IL-6, and confirmed by histopathological alterations. However, histone preconditioning significantly ameliorated the OJ-induced liver injury caused by BDL, as shown by an improvement in the levels of liver enzymes, a suppression of IL-6 production, as well as histopathological alterations. Therefore, these results suggested that histone preconditioning is able to protect against OJ-induced liver injury in rats.