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Forskolin, a hedgehog signalling inhibitor, attenuates carbon tetrachloride‐induced liver fibrosis in rats
Author(s) -
ElAgroudy Nermeen N,
ElNaga Reem N,
ElRazeq Rania Abd,
ElDemerdash Ebtehal
Publication year - 2016
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.13611
Subject(s) - forskolin , endocrinology , fibrosis , oxidative stress , hedgehog signaling pathway , medicine , hepatic stellate cell , chemistry , cyclopamine , hedgehog , pharmacology , signal transduction , biochemistry , stimulation
Background and Purpose Liver fibrosis is one of the leading causes of morbidity and mortality worldwide with very limited therapeutic options. Given the pivotal role of activated hepatic stellate cells in liver fibrosis, attention has been directed towards the signalling pathways underlying their activation and fibrogenic functions. Recently, the hedgehog (Hh) signalling pathway has been identified as a potentially important therapeutic target in liver fibrosis. The present study was designed to explore the antifibrotic effects of the potent Hh signalling inhibitor, forskolin, and the possible molecular mechanisms underlying these effects. Experimental Approach Male Sprague‐Dawley rats were treated with either CCl 4 and/or forskolin for 6 consecutive weeks. Serum hepatotoxicity markers were determined, and histopathological evaluation was performed. Hepatic fibrosis was assessed by measuring α‐SMA expression and collagen deposition by Masson's trichrome staining and hydroxyproline content. The effects of forskolin on oxidative stress markers (GSH, GPx, lipid peroxides), inflammatory markers (NF‐κB, TNF‐α, COX‐2, IL‐1β), TGF‐β1 and Hh signalling markers (Ptch‐1, Smo, Gli‐2) were also assessed. Key Results Hepatic fibrosis induced by CCl 4 was significantly reduced by forskolin, as indicated by decreased α‐SMA expression and collagen deposition. Forskolin co‐treatment significantly attenuated oxidative stress and inflammation, reduced TGF‐β1 levels and down‐regulated mRNA expression of Ptch‐1, Smo and Gli‐2 through cAMP‐dependent PKA activation. Conclusion and Implications In our model, forskolin exerted promising antifibrotic effects which could be partly attributed to its antioxidant and anti‐inflammatory effects, as well as to its inhibition of Hh signalling, mediated by cAMP–dependent activation of PKA.