Effect of bradykinin on nitric oxide production, urea synthesis and viability of rat hepatocyte cultures

BACKGROUND: It is well known that cytotoxic factors, such as lipopolysaccharides, derange nitrogen metabolism in hepatocytes and nitric oxide (NO) is involved among the other factors regulating this metabolic pathway. Hepatocytes have been shown to express large levels of NO following exposure to endotoxins, such as bacterial lipopolysaccharide and/or cytokines, such as tumour necrosis factor-α (TNFα), interleukin-1. The control role of arginine in both urea and NO biosynthesis is well known, when NO is synthesized from arginine, by the NOS reaction, citrulline is produced. Thus, the urea cycle is bypassed by the NOS reaction. Many authors demonstrated in other cellular types, like cardiomyocytes, that bradykinin caused the increase in reactive oxygen species (ROS) generation. The simultaneous increase of NO and ROS levels could cause peroxynitrite synthesis, inducing damage and reducing cell viability. The aim of this research is to study the effect of bradykinin, a proinflammatory mediator, on cell viability and on urea production in cultures of rat hepatocytes. RESULTS: Hepatocytes were treated with bradykinin, that stimulates nitric oxide synthase (NOS). NO release was determined using 4,5 diaminofluorescein diacetate (DAF-2DA), as fluorescent indicator of NO. Addition of the NOS inhibitor, N(g)-nitro-L-arginine methyl ester (L-NAME), to the culture medium inhibited the increase of NO production. Exposure of hepatocytes to bradykinin 0,1 mM for 2 hours resulted in a significant decrease of urea synthesis. Cell viability, instead, showed a significant decrease 24 hours after the end of bradykinin treatment as determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5diphenyl-2H-tetrazolium (MTT) assay. L-NAME addition recovered urea production and cell viability at control values. CONCLUSION: The findings suggest that the cell toxicity, after bradykinin treatment, effectively depends upon exposure to increased NO levels and the effects are prevented by L-NAME. The results show also that the increased NO synthesis induces a reduced urea production, that is another index of cell damage

Modelli avanzati per la simulazione delle scelte di viaggio degli utenti del trasporto pubblico locale

Dottorato di Ricerca in Tecnologie e Pianificazione Ambientale, Ciclo XX ,a.a.2006-2007Università della Calabri

Valutazione dello stress ossidativo e del danneggiamento cellulare indotto dai radicali liberi su preparati cellulari umani e animali in vitro: azione protettiva di agenti riducenti naturali

Dottorato di Ricerca in: Ambiente Salute e Processi Ecosostenibili, Ciclo XXIV, a.a. 2010-2011Università della Calabri

Extra virgin olive oil intake and the lower likelihood of being obese, hypertensive and diabetic

School “Life Sciences” PhD in “Health, Ambient and Eco-sustainable Processes, Ciclo XXVII, a.a. 2014University of Calabri

Analysis of human skin tissue by a skin-meter: A preliminary study

The aim of this study is to evaluate the skin elasticity in individuals who practise spinning. Mechanical eva- luations were conducted, under environmental and physical established conditions, during a physical training period. A total of 12 volunteers aged 35 ± 5 years were enrolled in this study, (60 min) before (control) and (60 min) after practicing spinning. Skin elasticity and area were measured by a Skin Meter and analysed with the Skin Meter software 1.3. In subjects who practiced spinning, the data shown a significant effect: on elasticity, evaluated as the ratio of final retraction (UA) and final distension (UF), on viscoelasticity express as the ratio delayed distension (UV) and immediate distension (UE); and on meas- urements of skin area vs control subjects. Skin Meter can be useful for a non-invasive screening of skin condition with also a potential extension in subjects with skin pathologies or to monitor skin oxidative stress in sportive subjects