Vitex negundo attenuates calpain activation and cataractogenesis in selenite models B.N. Rooban a , Y. Lija a , P.G. Biju a , V. Sasikala a , V. Sahasranamam b , Annie Abraham a, * a Department of Biochemistry, University of Kerala, Kariavattom, Thiruvananthapuram-695581, Kerala, India b Regional Institute of Ophthalmology, Medical College, Thiruvananthapuram-695037, India article info Article history: Received 8 January 2008 Accepted in revised form 13 November 2008 Available online 6 December 2008 Keywords: antioxidants flavonoids calpains oxidative stress quercetin selenite cataract Vitex negundo abstract Recent investigations have shown that phytochemical antioxidants can scavenge free radicals and prevent various diseases. Cataract is the leading cause of blindness and is associated with oxidative damage of the lens. Selenite-induced cataract in rat pups is an excellent mimic of oxidative stress- induced cataract. Selenite cataract is associated with oxidative stress, loss of calcium homeostasis, cal- pain activation and protein insolubilization in the lens. Our present study focuses on the isolation of flavonoids from Vitex negundo and to assess its efficacy in preventing these changes in the lens of selenite-induced cataract models. Eight-day-old Sprague-Dawley rat pups were used for the study and divided into four groups: Control (G I), Sodium selenite-induced (G II), Sodium selenite þ quercetin treated (G III), Sodium selenite þ flavonoids from Vitex negundo (FVN) (G IV). Cataract was induced by a single subcutaneous injection of Sodium selenite (4 mg/Kg body weight) on the 10th day. Treatment groups received quercetin (1.0 mg/Kg body weight) and FVN (1.0 mg/Kg body weight) intraperitoneally from 8th to 15th day. Cataract was visualized from the 16th day. Morphological examination of the rat lenses revealed no opacification in G I and mild opacification in G III and G IV (stage 1) whereas dense opacification in G II (stage 4–6). The activities of superoxide dismutase (SOD), catalase, Ca 2þ ATPase, concentration of reduced glutathione (GSH) and protein sulfhydryl content were significantly increased in G III and G IV compared to G II, while decreased activities of calpains, lower concentration of calcium and thiobarbituric acid reactive substances (TBARS) were observed in G III and IV as compared to G II. Lens protein profile of water soluble proteins showed normal levels of expression in treated groups compared to that of selenite-induced rats. These results indicate good antioxidant and therapeutic potential of FVN in modulating biochemical parameters against selenite-induced cataract, which have been reported in this paper for the first time. Ó 2008 Elsevier Ltd. All rights reserved. 1. Introduction Age-related cataract remains a major cause of blindness and its prevalence in developing countries is much more than that in the developed ones (Nirmalan et al., 2003). At present the most effective treatment of cataract is the surgical extirpation of the lens, but it possesses postoperative complications (Toda et al., 2007; Bock- elbrink et al., 2008). Hence, it is important to look into alternative pharmacological measures for the treatment of this disorder. Sele- nite-induced cataract (oxidative stress model) is an extremely rapid and convenient model of nuclear cataract in rats (Ostadalova et al., 1978). Major events of selenite cataract are loss of calcium homeo- stasis, reactive oxygen species generation, lipid peroxidation, calpain activation, insolubilization of proteins, decreased water soluble proteins and GSH (Shearer et al., 1997). Ionic homeostasis plays an essential role in lens transparency and the loss of Ca 2þ homeostasis has been implicated in cataract (Gupta et al., 2004). Pure nuclear cataracts which account for approximately 30% of cataracts, exhibit a normal internal ionic content while lenses with cortical cataract (pure or mixed) have increased lenticular calcium (Duncan and Bushell, 1975). Levels of Calcium in the lens are maintained in the sub-micromolar range by membrane Ca 2þ ATPase (Liu et al., 2002). Calpains (EC 3.4.22.17) are a family of calcium dependent neutral cysteine proteases and at least four proteolyti- cally active calpains are expressed in rodent lenses (Ma et al., 1999). These include ubiquitous calpains 1(m-calpain) and 2 (m-calpain) and lens-specific Lp82 and Lp85 (Shih et al., 2006). Oxidative stress has been identified as one of the major causes of age-related diseases including cataract (Salganik, 2001). Lens antioxidant status and lipid peroxidation products have been implicated in human cataract (Donma et al., 2002; Ganea and Harding, 2006). * Corresponding author. Tel.: þ91 471 2418078/2532220, 9447246692 (mobile); fax: þ91 471 2307158. E-mail address: annieab2@yahoo.co.in (A. Abraham). Contents lists available at ScienceDirect Experimental Eye Research journal homepage: www.elsevier.com/locate/yexer 0014-4835/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.exer.2008.11.020 Experimental Eye Research 88 (2009) 575–582