CCl 4 induces tissue-type plasminogen activator in rat brain; protective effects of oregano, rosemary or vitamin E Sophia N. Lavrentiadou a,⇑ , Maria P. Tsantarliotou a , Ioannis A. Zervos a , Efstathios Nikolaidis a , Marios P. Georgiadis b,1 , Ioannis A. Taitzoglou a a Department of Animal Structure and Function, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece b European Food Safety Authority (EFSA), Via Carlo Magno 1A, 43126 Parma, Italy article info Article history: Available online 4 July 2013 Keywords: Plasminogen activators Dietary antioxidants Culinary plants CCl 4 -toxicity Brain Rat abstract The high metabolic rate and relatively low antioxidant defenses of the lipid-rich brain tissue render it highly susceptible to reactive oxygen species (ROS) and oxidative stress, whereas the implication of ROS in the pathogenesis of several diseases in the central nervous system is well-established. The plas- minogen activator (PA) system is a key modulator of extracellular proteolysis, extracellular matrix remodeling and neuronal cell signaling and has been implicated in the pathogenesis of these diseases. This study evaluates the role of tissue-type PA (t-PA) in oxidative stress and the protective role of dietary antioxidants in the rat brain. We used the CCl 4 experimental model of ROS-induced lipid peroxidation and evaluated the antioxidant effect of oregano, rosemary or vitamin E. CCl 4 -treated Wistar rats exhibited elevated brain t-PA activity, which was decreased upon long-term administration of oregano, rosemary or vitamin E. PA inhibitor-1 (PAI-1) activity was also slightly elevated by CCl 4 , but this increase was not affected by the antioxidants. We hypothesize that the CCl 4 -induced t-PA activity indicates extracellular proteolytic activity that may be linked to neuronal cell death and brain damage. Vitamin E or antioxidants present in oregano or rosemary are effective in inhibiting t-PA elevation and can be considered as a potential protection against neuronal damage. Ó 2013 Published by Elsevier Ltd. 1. Introduction Tissue-type plasminogen activator (t-PA) is a serine-protease that activates plasmin, another serine-protease, via cleavage of plasminogen, thus initiating a potent proteolytic cascade. The activ- ity of t-PA is modulated by serpins [namely PA-inhibitor-1 (PAI-1) and neuroserpin], which bind t-PA and render it inactive. Although the t-PA/plasmin is a broad-spectrum proteolytic system, it has been studied mainly as a key modulator in haemostasis and fibrin clot degradation. However, a plethora of data indicates broader and more complex functions of this system, an intriguing one being its role in the central nervous system (CNS). Tissue-type PA is ex- pressed by neurons, astrocytes, microglia and oligodentrocytes and has been implicated in the development and pathophysiology of CNS. Its role is manifested by its activity as a protease and/or as a modulator of cell signaling (Lemarchant et al., 2012; Melchor and Strickland, 2005; Tsirka, 2002; Yepes and Lawrence, 2004). Carbon tetrachloride (CCl 4 ) is a potent hepatotoxic agent used extensively to induce in vivo liver degeneration by oxidative stress. The lipid solubility of CCl 4 renders it readily available to cells. Hence, it is deposited and mediates injury not only in the liver but also in the CNS, kidneys and several other organs (Sanzgiri et al., 1997; Basu, 2003). The molecular mechanism underlying the toxic effects of CCl 4 involves lipid peroxidation (LPO), mediated by the free radicals that are generated during its metabolism. Administration of CCl 4 to rats induces release of hepatic enzymes, hepatocyte necrosis and production of LPO products, such as malondialdehyde (MDA) (Basu, 2003; Szymonik-Lesiuk et al., 2003; Recknagel et al., 1989). Elevated LPO can lead to oxidative stress when the antioxidant de- fenses of the system are surpassed. This is particularly important in the brain, an organ that relies for its function mainly on aerobic 0278-6915/$ - see front matter Ó 2013 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.fct.2013.06.049 ⇑ Corresponding author. Address: Laboratory of Physiology, Department of Animal Structure and Function, Faculty of Veterinary Medicine, Aristotle University of Thessaloniki, Main Campus, 54124 Thessaloniki, Greece. Tel.: +30 2310 999872; fax: +30 2310 999861. E-mail address: slavrent@vet.auth.gr (S.N. Lavrentiadou). 1 Disclaimer: The author Marios P. Georgiadis is employed with the European Food Safety Authority (EFSA) in its Biological Monitoring Unit that provides scientific and administrative support to EFSA’s scientific activities in the area of collection, collation, analyses and reporting of scientific and technical data in the fields of zoonoses, microbiological contaminants, antimicrobial resistance, foodborne outbreaks, animal populations and other biological hazards in animals, food and feed for the purpose of risk monitoring and risk assessment. At the time that Dr. Georgiadis’ contribution to the present article was finalized he was employed with the Aristotle University of Thessaloniki. The present article is published under the sole responsibility of the authors and may not be considered as an EFSA scientific output. The positions and opinions presented in this article are those of the authors alone and are not intended to represent the views or scientific works of EFSA. To know about the views or scientific outputs of EFSA, please consult its website under http:// www.efsa.europa.eu. Food and Chemical Toxicology 61 (2013) 196–202 Contents lists available at SciVerse ScienceDirect Food and Chemical Toxicology journal homepage: www.elsevier.com/locate/foodchemtox