ABSTRACT
The degree of neuroinflammation is correlated mainly with cognitive and motor dysfunctions associated with hepatic encephalopathy (HE). The current study was conducted to explore the possible protective potential of the antidiabetic drug; linagliptin (LNG; 10 or 20 mg/kg) against HE induced by thioacetamide (TAA) in rats. Animals received two consecutive intraperitoneal injections of TAA (200 mg/kg) on alternate days. Neurobehavioral tests were performed 24 h after the last injection, and rats were sacrificed 24 h later (48 h). The higher LNG dose more effectively protected against TAA-induced changes. Administration of LNG for 15 days before TAA notably mitigated TAA-induced acute liver injury and HE, as verified by the marked improvement in motor coordination, locomotor activity, and cognition function. LNG maintained both brain and liver weight indices and retracted the hyperammonemia with a prominent suppression in liver transaminases. This was accompanied by an evident modulation of hepatic and hippocampal oxidative stress markers; GSH and MDA. LNG attenuated both liver and hippocampal pro-inflammatory cytokine; IL-1ß while augmented the anti-inflammatory one; IL-10. It noticeably reduced hepatic and hippocampal COX-2 and TNF-α and maintained hepatic and brain architectures. It also induced a marked decrease in the inflammation-regulated transcription factor, C/EBP-ß, with a profound increase in hippocampi's anti-inflammatory chemokine, CX3CL1/Fractalkine. LNG modulated TAA-induced disturbances in hippocampal amino acids; glutamate, and GABA with a significant increase in hippocampal BDNF. In conclusion, the regulatory effect of LNG on neuroinflammatory signaling underlines its neuroprotective effect against progressive encephalopathy accompanying acute liver injury.
