ABSTRACT
In the present study, we aimed to delineate the neuroprotective potential of thymol (THY) against neurotoxicity and cognitive deterioration induced by thioacetamide (TAA) in an experimental model of hepatic encephalopathy (HE). Rats received TAA (100 mg kg-1, intraperitoneally injected, three times per week) for two weeks. THY (30 and 60 mg kg-1), and Vit E (100 mg k-1) were administered daily by oral gavage for 30 days after HE induction. Supplementation with THY significantly improved liver function, reduced serum ammonia level, and ameliorated the locomotor and cognitive deficits. THY effectively modulated the alteration in oxidative stress markers, neurotransmitters, and brain ATP content. Histopathology of liver and brain tissues showed that THY had ameliorated TAA-induced damage, astrocyte swelling and brain edema. Furthermore, THY downregulated NF-kB and upregulated GFAP protein expression. In addition, THY significantly promoted CREB and BDNF expression at both mRNA and protein levels, together with enhancing brain cAMP level. In conclusion, THY exerted hepato- and neuroprotective effects against HE by mitigating hepatotoxicity, hyperammonemia and brain ATP depletion via its antioxidant, anti-inflammatory effects in addition to activation of the CREB/BDNF signaling pathway.
Subject(s)
Hepatic Encephalopathy , Neurotoxicity Syndromes , Adenosine Triphosphate/metabolism , Animals , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , Cognition , Hepatic Encephalopathy/chemically induced , Hepatic Encephalopathy/drug therapy , Hepatic Encephalopathy/metabolism , Liver/metabolism , Neurotoxicity Syndromes/drug therapy , Neurotoxicity Syndromes/etiology , Neurotoxicity Syndromes/metabolism , Oxidative Stress , Rats , Rats, Wistar , Signal Transduction , Thioacetamide/toxicity , Thymol/pharmacologyABSTRACT
The objective of the current study is to investigate the effect of rice bran oil (RBO) on hepatic fibrosis as a characteristic response to persistent liver injuries. Rats were randomly allocated into five groups: the negative control group, thioacetamide (TAA) group (thioacetamide 100 mg/kg thrice weekly for two successive weeks, ip), RBO 0.2 and 0.4 groups (RBO 0.2mL and 0.4 mL/rat/day, po) and standard group (silymarin 100 mg/kg/day, po) for two weeks after TAA injection. Blood and liver tissue samples were collected for biochemical, molecular, and histological analyses. Liver functions, oxidative stress, inflammation, liver fibrosis markers were assessed. The obtained results showed that RBO reduced TAA-induced liver fibrosis and suppressed the extracellular matrix formation. Compared to the positive control group, RBO dramatically reduced total bilirubin, AST, and ALT blood levels. Furthermore, RBO reduced MDA and increased GSH contents in the liver. Simultaneously RBO downregulated the NF-κß signaling pathway, which in turn inhibited the expression of some inflammatory mediators, including Cox-2, IL-1ß, and TNF-α. RBO attenuated liver fibrosis by suppressing the biological effects of TGF-ß1, α-SMA, collagen I, hydroxyproline, CTGF, and focal adhesion kinase (FAK). RBO reduced liver fibrosis by inhibiting hepatic stellate cell activation and modulating the interplay among the TGF-ß1 and FAK signal transduction. The greater dosage of 0.4 mL/kg has a more substantial impact. Hence, this investigation presents RBO as a promising antifibrotic agent in the TAA model through inhibition of TGF-ß1 /FAK/α-SMA.
