Sublethal exposures of diazinon alters glucose homostasis in Wistar rats: Biochemical and molecular evidences of oxidative stress in adipose tissues Mohsen Pakzad, Shamileh Fouladdel, Amir Nili-Ahmadabadi, Nazila Pourkhalili, Maryam Baeeri, Ebrahim Azizi 1 , Omid Sabzevari, Seyed Nasser Ostad, Mohammad Abdollahi ⇑ Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences (TUMS), Iran article info Article history: Received 4 July 2012 Accepted 19 November 2012 Available online 19 December 2012 Keywords: Diazinon Glucose homostasis Organophosphorous Mechanism of toxicity Oxidative stress abstract Disorder of glucose homeostasis is one of the most important complications following exposure to organ- ophosphorous (OPs) pesticides. Regarding the importance of adipose tissue in regulating blood glucose and the role of oxidative stress in toxicity of OPs and in the continue of our previous works, in the present study we focused on tumor necrosis factor alpha (TNFa), glucose transporter type 4 (GLUT4), and nuclear factor kappa-light-chain-enhancer of activated B cells (Nf-jB) in a sublethal model of toxicity by diazinon as a common OPs. Following time-course study of various doses of diazinon in impairing blood glucose, dose of 70 mg/kg/ day was found the optimum. Animals were treated for 4 weeks and after gavage of glucose (2 g/kg), the glucose change was evaluated at time-points of 0, 30, 60, 120 and 180 min to identify oral glucose toler- ance test (GTT). In addition, serum insulin was measured in fasting condition. In adipose tissue, oxidative stress markers including reactive oxygen species (ROS), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and TNFa were evaluated. The mRNA expression of GLUT4, Nf-jB and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) were also determined by real time reverse transcription polymer- ase chain reaction (RT-PCR). Diazinon at dose of 70 mg/kg/day impaired GTT and diminished insulin level while augmented ROS, NADPH oxidase, and TNFa. The GLUT4 mRNA expression was amplified by diaz- inon while unlikely, the expression of Nf-jB gene did not change. On the basis of biochemical and molecular findings, it is concluded that diazinon impairs glucose homeostasis through oxidative stress and related proinflammatory markers in a way to result in a reduced function of insulin inside adipose tissue. Although, diazinon interfered with pancreatic influence on the adipose tissue most probably via stimulation of muscarinic receptors, current data are not suffi- cient to introduce adipose tissue as a target organ to OPs toxicity. Considering the potential of OPs to accumulate in adipose tissue, it seems a good candidate organ for future studies. Although, hyperglyce- mia was not induced by diazinon but increased AUC 0–180 min leads us to the point that diazinon induces kind of instability in glucose homostasis and diabetes. Ó 2012 Elsevier Inc. All rights reserved. 1. Introduction Diazinon (O,O-diethyl O-[4-methyl-6-(propan-2-yl) pyrimidin- 2-yl] phosphorothioate) is one of the most widely used organo- phosphorous (OP) pesticides in the agriculture and public health. The leading mechanism of toxicity of diazinon is inhibition of ace- tylcholinesterase (AChE), an enzyme involved in regulation of neu- rotransmission by hydrolysis of the acetylcholine (ACh). In the recent years, the potential of OPs in disturbing glucose homostasis and induction of diabetes has been confirmed. For instance, an epi- demiologic study indicated extra incidence of diabetes among OP applicators who worked between 1993 and 2003 in the US [1]. Rahimi and Abdollahi [2] reviewed the mechanisms and organs that are involved in induction of diabetes by OPs and pointed out that pancreatic Langerhans islets and the liver are two main in- volved organs. Panahi et al. [3] and Vosough-Ghanbari et al. [4] indicated that secretion of insulin is inhibited by OPs in the pres- ence of basal and provoked concentration of glucose. Jamshidi et al. [5] found that the enzyme glutamate dehydrogenase in Lan- gerhans islet is impaired by toxicity of OP and thus inappropriate insulin is released. Furthermore, study in the liver by Abdollahi et al. [6] indicated that malathion provokes glycogenolysis and glu- coneogenesis and disturbs glucose hemostasis. In muscles, Pour- nourmohammadi et al. [7] found that OPs elevate glycogenolysis and glycolysis that result in a rise in blood glucose. Shadnia et al. 0048-3575/$ - see front matter Ó 2012 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.pestbp.2012.11.008 ⇑ Corresponding author. E-mail addresses: mohammad.abdollahi@utoronto.ca, mohammad@tums.ac.ir (M. Abdollahi). 1 Equally contributed as corresponding author. Pesticide Biochemistry and Physiology 105 (2013) 57–61 Contents lists available at SciVerse ScienceDirect Pesticide Biochemistry and Physiology journal homepage: www.elsevier.com/locate/pest