Peroxisome Proliferator Activator Receptor (PPAR)-γ Ligand, but Not PPAR-α, Ameliorates Cyclophosphamide-Induced Oxidative Stress and Inflammation in Rat Liver

Hindawi Publishing Corporation PPAR Research Volume 2014, Article ID 626319, 10 pages http://dx.doi.org/10.1155/2014/626319 Research Article Peroxisome Proliferator Activator Receptor (PPAR)-𝛾 Ligand, but Not PPAR-𝛼, Ameliorates Cyclophosphamide-Induced Oxidative Stress and Inflammation in Rat Liver Azza A. K. El-Sheikh1 and Rehab A. Rifaai2 1 2 Department of Pharmacology, Faculty of Medicine, Minia University, Minia 61511, Egypt Department of Histology, Faculty of Medicine, Minia University, Minia 61511, Egypt Correspondence should be addressed to Azza A. K. El-Sheikh; Received 31 August 2013; Revised 9 March 2014; Accepted 10 March 2014; Published 2 April 2014 Academic Editor: Howard P. Glauert Copyright © 2014 A. A. K. El-Sheikh and R. A. Rifaai. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Hepatoprotective potential of peroxisome proliferator activator receptor (PPAR)-𝛼 and -𝛾 agonists, fenofibrate (FEN), and pioglitazone (PIO), respectively, against cyclophosphamide (CP)-induced toxicity has been investigated in rat. FEN and PIO (150 and 10 mg/kg/day, resp.) were given orally for 4 weeks. In separate groups, CP (150 mg/kg, i.p.) was injected as a single dose 5 days before the end of experiment, with or without either PPAR agonist. CP induced hepatotoxicity, as it caused histopathological alterations, with increased serum alanine and aspartate transaminases, total bilirubin, albumin, alkaline phosphatase and lactate dehydrogenase. CP caused hepatic oxidative stress, indicated by decrease in tissue reduced glutathione, with increase in malondialdehyde and nitric oxide levels. CP also caused decrease in hepatic antioxidant enzyme levels, including catalase, superoxide dismutase, glutathione peroxidase, and glutathione S-transferase. Furthermore, CP increased serum and hepatic levels of the inflammatory marker tumor necrosis factor (TNF)-𝛼, evaluated using ELISA. Preadministration of PIO, but not FEN, prior to CP challenge improved hepatic function and histology, and significantly reversed oxidative and inflammatory parameters. In conclusion, activation of PPAR-𝛾, but not PPAR-𝛼, conferred protection against CP-induced hepatotoxicity, via activation of antioxidant and anti-inflammatory mechanisms, and may serve as supplement during CP chemotherapy. 1. Introduction Cyclophosphamide (CP) is a synthetic alkylating agent that has for long been successfully used in treatment of cancer and autoimmune diseases, as well as in the prevention of organ transplantation rejection [1]. Despite of its tumor selectivity and wide range of clinical applications, CP is known to cause multiorgan damage that result in severe morbidity and might end fatally [2]. Most reports focused on studying CPinduced cardio- and gonadotoxicity [3–5], with much lesser attention to hepatotoxicity [6]. CP-induced hepatotoxicity may occur at high chemotherapeutic dosage [7] or even at lower concentrations attained during treating patients with autoimmune diseases [8, 9]. To date, the mechanisms involved in CP-induced hepatotoxicity are not completely clarified. It has been proposed that administration of CP might cause impairment of cellular respiration due to damage of mitochondrial energy converting mechanisms [10], which may interfere with hepatic intracellular oxidant/antioxidant balance and lead to accumulation of reactive oxygen species [11]. The resultant oxidative stress may then trigger nuclear factor-𝜅B (NF-𝜅B) inflammatory pathway, which increases hepatic intracellular proinflammatory cytokines as tumor necrosis factor (TNF)-𝛼 [12]. Fenofibrate (FEN) and pioglitazone (PIO) are peroxisome proliferator activator receptor (PPAR)-𝛼 and -𝛾 agonists that are used as antihyperlipidemic [13] and antidiabetic agents [14], respectively. We have recently shown that FEN 2 and PIO possessed comparable antioxidant, but not antiinflammatory, properties, and that they confer nephroprotection against toxicity of another anticancer drug, namely, methotrexate [15]. Still, the hepatic safety of these PPAR ligands has been controversial. FEN was reported to have hepatic favorable effects in some studies [16], whereas in others, FEN was reported to cause fatty liver in mice [17] and acute cholestatic hepatitis in humans [18]. Hepatic safety of PIO is also still controversial. While long term followup in a 3-year human study declared that PIO have no substantial hazard on the liver [19]; another study reported that PIO might be the cause of sporadic cases of liver failure [20]. Interestingly, both FEN [21, 22] and PIO [23, 24] were suggested to modulate hepatic oxidant/antioxidant parameters and inflammatory cytokines, which may suggest that they confer hepatoprotective effects. The objective of this study is to establish the potential use of PPAR-𝛼 and -𝛾 agonists, FEN, and PIO, respectively, as supplementary adjuvant to protect against CP-induced hepatotoxicity and to investigate the pharmacological mechanisms involved. 2. Materials and Methods 2.1. Chemicals. FEN and PIO were kind gifts from Sigma Pharmaceutical Industries and Medical Union Pharmaceuticals (Egypt), respectively. CP was purchased from Baxter Oncology (Germany). Kits for examining total bilirubin, albumin, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) in serum, as well as reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and glutathione S-transferase (GST) in liver homogenate were purchased from Biodiagnostic (Egypt). TNF-𝛼 enzyme-linked immunosorbent assay (ELISA) kit was purchased from WKEA-Med supplies Corp. (China). 2.2. Experimental Design. Forty-eight adult male albino rats (180–220 g) were purchased from the National Research Centre (Giza, Egypt). Rats were placed in the standard animal facility throughout the experiments, housed 4 animals per cage. Tap water and laboratory chow were freely accessed. The study protocol was consistent with the guidelines and approved by the Research Ethical Committee of Faculty of Medicine, Minia University. For 2 weeks before the start of experiments, animals were left to acclimatize. After acclimatization period, animals were divided into 6 groups (𝑛 = 8 each): control untreated group, FEN- and PIO-treated groups receiving single daily oral dose of 150 and 10 mg/kg/day of FEN and PIO, respectively [24, 25], by gastric gavage for 4 weeks, and CP-treated group receiving a single i.p. dose of 150 mg/kg 5 days before the end of the experiment [26]. Two other groups of combined CP/FEN and CP/PIO received CP, FEN, and PIO treatments as previously indicated. Total rat body weights were recorded before the start and at the end of the 4-week experiment. Percent of change in body weight was evaluated by calculating the pe (...truncated)