Endothelin receptor inhibition with bosentan delays onset of liver injury in streptozotocin-induced diabetic condition.

Background: This study was designed to investigate the protective effects of bosentan an orally active non-peptide mixed ETA/ETB receptor antagonist, on liver injury in streptozotocin-induced diabetic rats.
Methods: 24 Albino-Wistar rats were randomly divided into 4 groups: healthy (Group 1), diabetic (Group 2) (60 mg/kg of streptozotocin i.p.), diabetic treated with bosentan 50 mg/kg (Group 3) and diabetic treated with bosentan 100 mg/kg (Group 4). The treatment of bosentan was initiated after streptozocin injection and continued for 60 days.
Results: Liver from diabetic rats showed significant increase in malondialdehyde (MDA) level and significant decrease in glutathione (GSH), and superoxide dismutase (SOD) activity. Endothelin (ET-1), tumor necrosis factor (TNF-α) and transforming growth factor beta (TGF-β) gene expression significantly increased in the diabetic groups in the rat liver tissue. Bosentan treatment showed a significant up-regulatory effect on ET-1, TNF-α and TGF-β mRNA expression. Results from histopathological evaluation of the liver were in accordance with our biochemical and molecular results.
Conclusions: These data provide clear evidence that bosentan treatment is associated with promising hepatoprotective effect against diabetes-induced liver damage via reduction of cell inflammation and oxidative damage. These data suggest that ET receptors may be an important actor in diabetes-related liver damage, and blockage of these receptors may become a target for preventing diabetic complications in the future.
(© Georg Thieme Verlag KG Stuttgart · New York.)