Contents lists available at ScienceDirect Toxicology and Applied Pharmacology journal homepage: www.elsevier.com/locate/taap Nano-sized titanium dioxide toxicity in rat prostate and testis: Possible ameliorative effect of morin Nancy N. Shahin a,⁎ , Maha M. Mohamed b a Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt b Department of Home Economics, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt ARTICLE INFO Keywords: Nano-sized titanium dioxide Morin Prostate Testis Spermatogenesis Steroidogenesis ABSTRACT This study investigated the effect of short-term oral exposure to nano-sized titanium dioxide (nTiO 2 ) on Wistar rat prostate and testis, and the associating reproductive-related alterations. The study also evaluated the po- tential ameliorative effect of the natural flavonoid, morin, on nTiO 2 -induced aberrations. Intragastric admin- istration of nTiO 2 (50 mg/kg/day for 1, 2 and 3 weeks) increased testicular gamma-glutamyltransferase (γ-GT) activity and decreased testicular steroidogenic acute regulatory protein (StAR) and c-kit gene expression, serum testosterone level and sperm count. nTiO 2 -treated rats also exhibited prostatic and testicular altered glutathione levels, elevated TNF-α levels, up-regulated Fas, Bax and caspase-3 gene expression, down-regulated Bcl-2 gene expression and enhanced prostatic lipid peroxidation. Sperm malformation and elevated testicular acid phos- phatase (ACP) activity and malondialdehyde level, serum prostatic acid phosphatase activity, prostate specific antigen (PSA), gonadotrophin and estradiol levels occurred after the 2 and 3 week regimens. Morin (30 mg/kg/ day administered intragastrically for 5 weeks) mitigated nTiO 2 -induced prostatic and testicular injury as evi- denced by lowering serum PSA level, testicular γ-GT and ACP activities and TNF-α level, along with hampering both intrinsic and extrinsic apoptotic pathways. Moreover, morin alleviated prostatic lipid peroxidation, raised prostatic glutathione level, and relieved testicular reductive stress. Additionally, morin increased testicular StAR and c-kit mRNA expression, raised the sperm count, reduced sperm deformities and modified the altered hor- mone profile. Histopathological evaluation supported the biochemical findings. In conclusion, morin could ameliorate nTiO 2 -induced prostatic and testicular injury and the corresponding reproductive-related aberrations via redox regulatory, anti-inflammatory and anti-apoptotic mechanisms, promoting steroidogenesis and sper- matogenesis, and improving sperm count and morphology. 1. Introduction Nano-sized titanium dioxide (nTiO 2 ) particles are being extensively used in various applications including food industry, paints, cosmetics, sunscreens, implanted medical devices and pharmaceutical prepara- tions. The widespread use of nanomaterials is based on their unique physicochemical properties, including small size, large surface area to volume ratio and high reactivity potential (Cunningham et al., 2002). However, such properties render them more reactive in a cell and in- crease their ability to produce reactive oxygen species (ROS) (Hong et al., 2015). The wide use of TiO 2 nanoparticles enhances the probability of exposure via several routes such as inhalation, injection, oral ingestion and the dermal route. The gastrointestinal tract could be a significant route for the absorption of TiO 2 nanoparticles since they are being used on a large scale in food products, nutritional supplements, water and liquid beverages, food colorants, personal care products such as toothpastes, and drug carriers (Hagens et al., 2007; Lomer et al., 2002), suggesting a potentially high incidence of oral exposure to nTiO 2 . Many in vivo and in vitro studies have revealed that increased ex- posure to TiO 2 nanoparticles could cause inflammatory reaction (Hong et al., 2016), oxidative DNA damage (Meena et al., 2015) and serious damage to the liver, kidneys, lungs and myocardium (Li et al., 2017; Liu et al., 2009). The endocrine system seems to be a target of nTiO 2 (Tassinari et al., 2014) and the male reproductive system is particularly highly susceptible (Meena et al., 2015). Although there are several http://dx.doi.org/10.1016/j.taap.2017.08.014 Received 9 May 2017; Received in revised form 7 July 2017; Accepted 23 August 2017 ⁎ Corresponding author at: Department of Biochemistry, Faculty of Pharmacy, Cairo University, Kasr El-Eini Street, Cairo 11562, Egypt. E-mail address: nancy.shahin@pharma.cu.edu.eg (N.N. Shahin). Abbreviations: ACP, acid phosphatase; FSH, follicle stimulating hormone; γ-GT, gamma-glutamyltransferase; GSH, glutathione; LH, luteinizing hormone; MDA, malondialdehyde; nTiO 2 , nano-sized titanium dioxide; PAP, prostatic acid phosphatase; PSA, prostate specific antigen; ROS, reactive oxygen species; StAR, steroidogenic acute regulatory protein; TNF-α, tumor necrosis factor-alpha Toxicology and Applied Pharmacology 334 (2017) 129–141 Available online 26 August 2017 0041-008X/ © 2017 Elsevier Inc. All rights reserved. MARK