Fas Receptor Activation by Endogenous Opioids Is A New Mechanism for Cardiomyopathy in Cirrhotic Rats

J Clin Exp Hepatol. 2017 Jun;7(2):107-114. doi: 10.1016/j.jceh.2016.10.002. Epub 2016 Oct 17.

Abstract

Background: Cirrhosis, a common consequence of chronic liver inflammation is associated with various cardiovascular dysfunctions which are called cirrhotic cardiomyopathy (CC). Among the various possible causes of CC, apoptosis is considered to have a pivotal role.

Objectives: To explore the contribution of endogenous opioids in the apoptosis process in a rat model of CC.

Material and methods: Four genes were selected to cover both intrinsic and extrinsic pathways of apoptosis. Cardiac samples from 4 groups of rats were evaluated. Two groups were cirrhotic through bile duct ligation (BDL) receiving either naltrexone (BDL-naltrexone) or saline (BDL-saline), two others were normal rats as sham groups receiving either naltrexone (sham-naltrexone) or saline (sham-saline). Expression level of BCL2, Caspase3, Fas and FasL was explored in all groups using reverse transcriptase real-time PCR.

Results: BDL-saline group showed significant over-expression of BCL2, caspase3 and Fas. BCL2 expression was 1.44 (P < 0.001) and caspasse3 was 1.35 (P < 0.001) times higher than sham-saline group, Fas was also overexpressed 1.3 (P < 0.001) times higher than BDL-naltrexone group and 1.91 (P < 0.001) compared to sham-naltrexone group. Caspase3 expression was 1.35 (P < 0.001) folds higher than sham-naltrexone group. The expression pattern of FasL revealed no statistically significant change among study groups.

Conclusion: Fas molecule enrollment during CC is a novel finding. Fas molecule is activated during cirrhosis through elevated levels of endogenous opioids. This pathway is one of the leading causes of CC. Our findings also demonstrated the protective role of naltrexone as opioids antagonist on cardiomyocytes in a rat model of CC.

Keywords: BDL, bile duct ligation; CC, cirrhotic cardiomyopathy; Fas; H&E, Hematoxylin and Eosin; MAPKs, mitogen-activated protein kinases; NO, nitric oxide; apoptosis; cirrhotic cardiomyopathy; opioid; qRT-PCR, Real-Time Reverse Transcription PCR.