Abstract
Endocrine disrupting effects have become a major issue in the field of environmental toxicology. Due to the testicular toxicity reported for acrylamide and confirmed in our study, and the double jeopardy with its well-documented carcinogenicity following leaching out from overcooked starchy foods, the current study was extended to address the possible protective effects of two nutraceuticals.
The present study was designed to assess the possible reproductive toxicity of acrylamide in adult male Swiss albino rats. Also, the work was extended to investigate the potential protective effects of two nutraceuticals namely; thymoquinone (TQ) and capsaicin against acrylamide-induced reproductive toxicity.
Sixty male albino rats were allotted into six groups. Group 1: Rats received free tap water and served as control group. Group 2: Rats received acrylamide in a daily dose and served as the model. Group 3: Rats were administered TQ twice weekly. Group 4: Rats were administered capsaicin once daily. Group 5: Rats challenged with acrylamide were administered TQ twice weekly. Group 6: Rats challenged with acrylamide were administered capsaicin once daily.
A murine model of acrylamide testicular toxicity was reproduced and was characterized biochemically, morphologically and histologically. Acrylamide increased oxidative stress, expression of testicular NF-κB/p65, in addition down regulated the expression of occludin that may further account for its testicular toxicity. Both nutraceuticals; TQ and capsaicin have proven more or less efficacy in ameliorating all the toxic insults exerted by acrylamide in the current reproductive toxicity model.
Key words: Testicular failure; Thymoquinone; Capsaicin; Acrylamide; NF-ΚB/P65; Occludin.
Abbreviations
Thymoquinone (TQ); nuclear factor kappa B (NF-κB/p65); luteinizing hormone (LH); follicle stimulating hormone (FSH); lactate dehydrogenase isoenzyme-X (LDH-X); reduced glutathione (GSH); superoxide dismutase (SOD); thiobarbituric acid reactive substances (TBARS); catalase (CAT); malondialdehyde (MDA).
Introduction
Acrylamide is a versatile organic compound that finds its way into many products in our everyday life. Acrylamide has been found to occur in many cooked starchy foods and is of concern as a possible carcinogen. Acrylamide was accidentally discovered in foods in April 2002 by scientists in Sweden when they found the chemical in starchy foods, such as potato chips, French fries, and bread that had been heated above120° (Tareke, Rydberg, Karlsson, Eriksson, & Törnqvist, 2002). Apart from its possible carcinogenic effects, acrylamide has shown reproductive toxicity in rats (Parzefall, 2008) and(Abdel-Fattah, Matsumoto, & Watanabe, 2000). However, the precise mechanism(s) are not fully explored.
Nutraceutical, a portmanteau of the words “nutrition” and “pharmaceutical”, is a food or food product that reportedly provides health and medical benefits, including the prevention and treatment of diseases (Yadav, PATIL, & Gupta, 2013). Such products may range from isolated nutrients, dietary supplements and specific diets to genetically engineered foods, herbal products, and processed foods such as cereals, soups, and beverages (Parvez, Malik, Ah Kang, & Kim, 2006). They provide health and medical benefits that delay, prevent and treat chronic inflammatory diseases due to the presence of the phytochemicals. Their beneficial effects reside for the most part on their anti-oxidative role that can reduce the level of ROS and free radicals, beside its powerful anti-inflammatory actions (Pyun, Kim, Han, Hong, & Lee, 2014).
Thymoquinone (TQ) is a phytochemical nutraceutical found in the plantNigella sativa. It has antioxidant effects, and has been shown to protect against heart, liver and kidney damage in animal studies, as well as having possible anti-cancer effects (B Aggarwal et al., 2011). It also has analgesic (Abdel-Fattah et al., 2000) (and anticonvulsant effects in animal models (Hosseinzadeh & Parvardeh, 2004).
Capsaicin is the main capsaicinoid in chili peppers. Capsaicin is currently used in topical ointments, as well as a high-dose dermal patch, to relieve the pain of peripheral neuropathy such as post-herpetic neuralgia caused by shingles (Chhabra, Aseri, Goyal, & Sankhla, 2012). Many pharmacological studies have used capsaicin as a tool to activate many physiological systems, with an emphasis on pain research, but also including functions such as the cardiovascular system, the respiratory system, and the urinary tract (O’Neill et al., 2012).
Taken together, the current study has been conducted to address the possible protective effects of two nutraceuticals, well known for their potential anti-oxidant and anti-inflammatory effects namely; TQ and capsaicin in acrylamide-challenged male rats.
The main objectives of the current study; to identify the possible mechanisms whereby acrylamide may induce damage in testicular and edpididymal tissues following the toxic insult with the xenobiotic. In addition, address the potential chemopreventive effects of the test compounds under investigation, and the possible underlying mechanism(s) with special emphasis on occludin as a tight junction protein crucial for the integrity of the basement membrane of the blood testes barrier, and nuclear factor kappa B (NF-κB/P65) as a marker of inflammation that would ultimately signal an adverse change to spermatogenesis after toxic insult.