The Role of RAAS Inhibition by Aliskiren on Paracetamol-Induced Hepatotoxicity Model in Rats.

Paracetamol is one of the most popular and widely used analgesic and antipyretic agents, but an overdose can cause hepatotoxicity and lead to acute liver failure. Aliskiren directly inhibits renin which downregulates the renin-angiotensin-aldosterone system (RAAS). Recent findings suggest that RAAS system takes part in the pathogenesis of liver fibrosis. We aimed to reveal the relationship between hepatotoxicity and the RAAS by examining paracetamol induced hepatotoxicity. Rats were separated into five groups as follows: control, 100 mg/kg aliskiren (p.o.), 2 g/kg paracetamol (per os (p.o.)), 2 g/kg paracetamol + 50mg/kg aliskiren (p.o.), and 2 g/kg paracetamol + 100 mg/kg aliskiren(p.o.). Samples were analyzed at the biochemical, molecular, and histopathological levels. Paracetamol toxicity increased alanine aminotransferases (ALT), aspartate aminotransferases (AST), renin, and angiotensin II levels in the serum samples. In addition, the SOD activity and glutathione (GSH) levels decreased while Lipid Peroxidation (MDA) levels increased in the livers of the rats treated with paracetamol. Paracetamol toxicity caused a significant increase in TNF-α and TGF-ß. Both aliskiren doses showed an improvement in ALT, AST, oxidative parameters, angiotensin II, and inflammatory cytokines. Only renin levels increased in aliskiren treatment groups due to its pharmacological effect. A histopathological examination of the liver showed that aliskiren administration ameliorated the paracetamol-induced liver damage. In immunohistochemical staining, the expression of TNF-α in the cytoplasm of the hepatocytes was increased in the paracetamol group but not in other treatment groups when compared to the control group. In light of these observations, we suggest that the therapeutic administration of aliskiren prevented oxidative stress and cytokine changes and also protected liver tissues during paracetamol toxicity by inhibiting the RAAS.

Protective effects of lithium: a new look at an old drug with potential antioxidative and anti-inflammatory effects in an animal model of sepsis.

Sepsis is the systemic response of an organism against microorganisms and toxins. Lithium is a therapeutic agent used for bipolar disorder and neurodegenerative disease, and it exerts pleiotropic effects on various cellular processes. The present study aimed to determine the effect of lithium on cecal ligation and puncture (CLP)-induced tissue injury in the lungs, by inhibiting the pro-inflammatory cytokine response, and the generation of reactive oxygen species (ROS) triggered by polymicrobial sepsis. Five groups of 20 rats each were used: 1) sham-operated control group; 2) CLP group; 3) 50mg/kg lithium-treated control healthy group; 4) 25 mg/kg lithium-treated CLP group; and 5) 50 mg/kg lithium-treated CLP group. A CLP polymicrobial sepsis model was applied to the rats. All rat groups were killed 16 h later, and lung and blood samples were analyzed histopathologically and biochemically. The 25 and 50 mg/kg of lithium decreased the level of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6), and the tumor necrosis factor-α (TNF-α) in the serum, and the 8-iso-prostaglandin F2α (8-ISO) level in lung tissue. The lithium also increased the activity of superoxide dismutase (SOD) and the total levels of glutathione (GSH) in the lung tissues of rats. The histopathological scores and examinations were in accordance with the biochemical results, and revealed significant differences in the inflammation scores between the sepsis group and the other groups. The CLP+lithium 50mg/kg group had the lowest inflammation score among the CLP groups. Our results indicated that the therapeutic administration of lithium prevented oxidative stress changes and cytokine changes, and also protected vital tissues.