Toxicology 272 (2010) 17–22 Contents lists available at ScienceDirect Toxicology journal homepage: www.elsevier.com/locate/toxicol A study to correlate rotenone induced biochemical changes and cerebral damage in brain areas with neuromuscular coordination in rats S. Swarnkar a , S. Singh a , R. Mathur b , I.K. Patro b , C. Nath a,∗ a Division of Toxicology, Central Drug Research Institute (CSIR), Lucknow 226001 (U.P.), India b School of Studies in Neuroscience, Jiwaji University, Gwalior 474011 (M.P.), India article info Article history: Received 16 February 2010 Received in revised form 16 March 2010 Accepted 29 March 2010 Available online 3 April 2010 Keywords: Rotenone Triphenyl trizolium chloride (TTC) Pesticide Oxidative stress Neuromuscular coordination abstract Rotenone induces neurotoxicity but its correlation with biochemical and cerebral changes in rat brain regions are not well defined. In the present study rotenone was administered (3, 6 and12 g/l) intran- igrally in adult male SD rats and its effect was assessed on neuromuscular coordination and in different brain areas viz. striatum (STR), mid-brain (MB), frontal cortex (FC) and hippocampus (HP) cerebral and biochemical changes on 1st and 7th day after treatment. All the doses of rotenone significantly impaired neuromuscular coordination performance on Rota rod test on 1st and 7th day. TTC staining showed significant increase in cerebral injury volume on 1st and 7th day after rotenone treatment indicating mitochondrial enzyme deficiency but increase after 7th day was less that after 1st day. Rotenone treated rats showed significant decrease in GSH and increase in MDA in different brain regions though the pattern was varied. After 1 day of rotenone (6 and 12 g) treatment significant decrease in GSH was observed in STR and MB while MDA was significantly increased only in MB. The maximal effect on GSH and MDA was obtained in STR and MB on 7th day after treatment with 12 g dose of rotenone. Thus, based on the occurrence of changes, it may be suggested that impairment of neuromuscular coordination is inked to oxidative stress rather than mitochondrial enzyme deficiency, all the processes are correlated with each other with the progression of time. MB appeared as most sensitive brain area towards rotenone toxicity. © 2010 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Several pesticides, viz. maneb, paraquat, dieldrin, and rotenone are potential risk factors in humans because of their reported neurotoxicity in animal models (Liu et al., 2003). Interestingly many of them have major site of action in mitochondrial elec- tron transport chain (Espoti, 1998). Rotenone, a pesticide derived from the roots of plants of Leguminosae family, freely cross cell membranes and causes neurotoxicity via inhibiton of complex I of the mitochondrial electron transport chain (Talpade et al., 2000), and ROS production (Uversky, 2004). Behavioral, pathological and biochemical lesions were reported after chronic intrajugu- lar administration of rotenone (Betarbet et al., 2000). Alam and Schmidt (2002) found dose dependent behavioral abnormalities in rats after chronic intraperitoneal injection of rotenone. Talpade et al. (2000) showed a heterogeneous distribution of rotenone in brain. Our earlier study in brain homogenates suggested that  CDRI Comm. no. 04/2010/CN. ∗ Corresponding author at: Division of Toxicology, Central Drug Research Insti- tute, P.O. Box 173, Lucknow 226001, India. Tel.: +91 522 2212411x4259; fax: +91 522 2623405. E-mail address: cnathcdri@rediffmail.com (C. Nath). susceptibility to rotenone induced oxidative damage may not be similar among the different brain areas due to variability in intracel- lular antioxidant system (Swarnkar et al., 2009). However, specific brain regions oriented in vivo neurotoxicity studies are lacking. The present study was done to investigate rotenone induced neu- rotoxicity in an in vivo set up to correlate oxidative stress and cerebral damage in brain areas with neurological deficit. The assessment of cerebral damage by the oxidation-reduction indi- cator 2,3,5-triphenyltetrazolium chloride (TTC) and biochemical changes by oxidative stress markers-reduced glutathione (GSH) and malondialdehyde (MDA) concentration along with neuromus- cular impairment using rota rod test. Sequence of rotenone induced effects at different time points – early (1 day) and later (7 days) was evaluated to find out correlation amongst changes in neuromuscu- lar coordination, oxidative stress and cerebral damage. 2. Materials and methods 2.1. Materials The chemicals: rotenone, DMSO (dimethyl sulphoxide) 5,5 ′ -dithiobis 2- nitrobenzoic acid (DTNB), thiobarbituric (TBA) were procured from Sigma Chemicals Co. (St. Louis, MA, USA). Trichloroacetic acid (TCA) obtained from Qualigens. Anes- thetic ether and Folin reagent were purchased from Sisco Research Laboratories Limited, Mumbai, India. 0300-483X/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.tox.2010.03.019