Roflumilast counteracts high-dose dexamethasone-induced steatohepatitis, metabolic abnormalities and aortic injury via inhibiting TNF-α/NF-κB, NLRP3/IL-1β and ER stress sensors

INTRODUCTION: High-dose dexamethasone (DEX) is used for management of severe conditions. However, the multisystem adverse effects induced by glucocorticoids represent a hindering stone toward the effective clinical use of such agents. Various initiatives have been taken to ameliorate these complications with limited success. AIM: The present study aims to explore the beneficial effects of roflumilast (ROF), a phosphodiesterase-4 (PDE-4) inhibitor, to combat DEX-induced steatohepatitis, metabolic abnormalities and aortic degeneration. RESULTS: The application of ROF (2.5 and 5 mg/kg) has reverted the hepatic and aortic histopathological abnormalities as well as the rise in serum liver enzymes induced by DEX. Such palliative effect is probably attributed to PDE-4 inhibition (↑cAMP) that subsequently regulates multiple effectors. The chemotaxis of inflammatory cells (MCP-1) was inhibited by ROF treatments which was linked to inhibition of extracellular ROS production (MDA and NO) as well as restoration of cellular antioxidant defense (GSH). DEX challenge was associated with activation of the inflammatory pathways including TNF-α/NF-κB and NLRP3/IL-1β that were significantly dampened in the ROF groups. The oxidative stress as well as activation of inflammatory pathways exerted by DEX has contributed to the activation of endoplasmic reticulum stress (CHOP and PERK) posing more threats to the insulted cells, however, fortunately, ROF treatments showed inhibited activation of ER stress sensors and thereby abstaining the cells from inevitable damage. The metabolic abnormalities induced by DEX including elevated fasting insulin and heightened AUC of blood glucose level upon application of oral glucose tolerance test were significantly improved by ROF treatment. CONCLUSION: The findings of our study depicted the hepatoprotective and metabolic regulating potentials of ROF in a rat model of DEX- induced steatohepatitis. Thereby, enhancing the overall efficacy and safety of DEX use in management of various disorders.