Protective effect of dieckol against chemical hypoxia-induced cytotoxicity in primary cultured mouse hepatocytes

Abstract

Hepatic ischemic injury is a major complication arising from liver surgery, transplantation, or other ischemic diseases, and both reactive oxygen species (ROS) and pro-inflammatory mediators play the role of key mediators in hepatic ischemic injury. In this study, we examined the effect of dieckol in chemical hypoxia-induced injury in mouse hepatocytes. Cell viability was significantly decreased after treatment with cobalt chloride (CoCl₂), a well-known hypoxia mimetic agent in a time- and dose-dependent manner. Pretreatment with dieckol before exposure to CoCl₂ significantly attenuated the CoCl₂-induced decrease of cell viability. Additionally, pretreatment with dieckol potentiated the CoCl₂-induced decrease of Bcl-2 expression and attenuated the CoCl₂-induced increase in the expression of Bax and caspase-3. Treatment with CoCl₂ resulted in an increased intracellular ROS generation, which is inhibited by dieckol or N-acetyl cysteine (NAC, a ROS scavenger), and p38 MAPK phosphorylation, which is also blocked by dieckol or NAC. In addition, dieckol and SB203580 (p38 MAPK inhibitor) increased the CoCl₂-induced decrease of Bcl-2 expression and decreased the CoCl₂-induced increase of Bax and caspase-3 expressions. CoCl₂-induced decrease of cell viability was attenuated by pretreatment with dieckol, NAC, and SB203580. Furthermore, dieckol attenuated CoCl₂-induced COX-2 expression. Similar to the effect of dieckol, NAC also blocked CoCl₂-induced COX-2 expression. Additionally, CoCl₂-induced decrease of cell viability was attenuated not only by dieckol and NAC but also by NS-398 (a selective COX-2 inhibitor). In conclusion, dieckol protects primary cultured mouse hepatocytes against CoCl₂-induced cell injury through inhibition of ROS-activated p38 MAPK and COX-2 pathway.

• Cobalt chloride
• dieckol
• hypoxic cell injury
• mouse hepatocytes
• reactive oxygen species

Acknowledgments

This work was supported by a grant from the Next-Generation BioGreen 21 Program (No. PJ009090), Rural Development Administration; National Research Foundation (NRF) grant funded by the Korean government (MSIP) (NRF-2012R1A4A1028835); Kyungpook National University Research Fund, 2013, Republic of Korea.

Declaration of interest

None declared.