721 Original article doi: 10.1016/S2222-1808(15)60920-3 ©2015 by the Asian Pacific Journal of Tropical Disease. All rights reserved. Acute toxicity of caprine alpha S2-casein protein on the microstructures and mineral profles of rat ileum Vita Agustina 1 , Bambang Setiawan 2 , Fatchiyah Fatchiyah 1* 1 Department of Biology, Faculty of Mathematic and Natural Sciences, Brawijaya University, Malang 65145, East Java, Indonesia 2 Department of Medical Chemistry and Biochemistry, Medical Faculty, Lambung Mangkurat University, Banjarmasin, South Kalimantan, Indonesia Asian Pac J Trop Dis 2015; 5(9): 721-725 Asian Pacific Journal of Tropical Disease journal homepage: www.elsevier.com/locate/apjtd *Corresponding author: Prof. Fatchiyah Fatchiyah, PhD, Department of Biology, Faculty of Mathematic and Natural Sciences, Brawijaya University, Jl. Veteran, Malang 65145, Indonesia. Tel: +62341 575841 E-mail: fatchiya@ub.ac.id Foundation Project: Supported by BOPTN-RU PTN UB decentralization research grant of 2012-2014. 1. Introduction Caprine casein protein contains mainly in αS1-, αS2-, β- and κ-casein, of which those types of casein have different properties and bioactive functions[1,2]. Bioactive peptides have potential as antibacterial, immunomodulatory, antioxidant, antithrombotic and antiinflammation activities[3-5]. Casein is potential as well to be developed as a source of nutrients for the body. Casein derived a lot of bioactive peptides that have a health benefit to control molecular and/or cellular signaling mechanism. Recently in our study, we had identified that the molecular weight of caprine αS2-casein (CSN1S2) protein is separately electroporated at 36 kDa, in contrast we did not find in bovine protein. The function of 36 kDa CSN1S2 protein had been characterized as proper. This study reported that CSN1S2 (αS2) protein isolated from Etawah goat milk consists of 223 amino acids and 8 bioactive peptides, so that there are many interactive sites for negatively and/or positively charged molecules[6]. Our previous in vitro study reported that CSN1S2 affected the proliferation of preosteblast cells[7]. Furthermore, in vivo study also supported the inflammatory effect of this casein on complete Freund’s adjuvant induced rheumatoid arthritis rats[8]. Ileum, the final part of the small intestine, performs the function of absorbing nutrients which have been processed by the stomach. The ileum consists of 4 layers: mucosa, sub-mucosa, muscularis propria (oriented smooth muscles fibers) and outer serosa layer. Mucosa epithelium folds to form villi that increase surface area and sub-mucosa embodies glands that secrete digestive enzymes[9]. Observation using scanning electron microscope (SEM) showed that mucosal villi are shaped like fingers which protrude into the lumen. The villous surface is almost entirely covered with enterocytes that act as absorptive cells[10]. Through absorption in the ileum, milk proteins including the CSN1S2 proteins are broken down into ARTICLE INFO ABSTRACT Objective: To determine the microstructures and mineral profiles of ileum villi in rats treated acutely with caprine αS2-casein (CSN1S2) protein isolated from Etawah goat milk. Methods: Fifty (male and female) rats were divided into 5 groups, including a group of rats- untreated as a control (untreated) and rats-treated with caprine CSN1S2 protein at doses of 500, 1 000, 2 000, and 4 000 mg/kg body weight by oral single dosage. The microstructures were analyzed by scanning electron microscope. The mineral profiles of ileum were measured by scanning electron microscope-energy dispersive X-ray software version 1.7. The degree of ileum perforation was calculated by BoneJ software. Results: The ileum microstructure of the control group showed a smooth and compact surface, while the treating groups showed less compact surface and minimal perforation. The levels of sodium, sulphur and phosphorus were statistically significant higher in treating females at all doses compared to the control (P < 0.05). In contrast, the selenium levels were significantly lower in treating females at all doses than that of the control group (P < 0.05). Conclusions: This research concludes that the caprine CSN1S2 protein is able to stimulate the ileum toxicity up to 2 000 mg/kg body weight dosage and change sodium, phosphorus, sulphur and selenium homeostasis of ileum in female rats. Contents lists available at ScienceDirect Article history: Received 25 May 2015 Received in revised form 26 May 2015 Accepted 1 Jun 2015 Available online 16 Jul 2015 Keywords: Acute toxicity Intestine Functional food Etawah goat milk