Please cite this article in press as: Truter, D., et al., Mucin secreting cells in the stomach and colon are altered by combination antiretroviral treatment in an obese rat model. Acta Histochemica (2016), http://dx.doi.org/10.1016/j.acthis.2016.11.014 ARTICLE IN PRESS G Model ACTHIS-51142; No. of Pages 7 Acta Histochemica xxx (2016) xxx–xxx Contents lists available at ScienceDirect Acta Histochemica journal homepage: www.elsevier.de/acthis Mucin secreting cells in the stomach and colon are altered by combination antiretroviral treatment in an obese rat model Danélle Truter a , Hans Strijdom b , Frans Everson b , Sanet H. Kotzé a,∗ a Division of Anatomy and Histology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 241, Cape Town, South Africa b Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, PO Box 241, Cape Town, South Africa a r t i c l e i n f o Article history: Received 26 October 2016 Received in revised form 10 November 2016 Accepted 10 November 2016 Available online xxx Keywords: Antiretroviral treatment Biofilm Obesity Gastrointestinal tract Mucins Histochemistry a b s t r a c t Mucins, secreted by intestinal goblet cells, form an integral part of the intestinal biofilm, which is impor- tant for the functioning of a healthy gastrointestinal tract (GIT). This mucous layer is sensitive to factors such as diet, drugs and inflammation. Histochemically, mucins can be classified as neutral or acidic, where acidic mucins can contain sulphate groups (sulphomucins) or sialic acid (sialomucins). The aim of the present study was to determine the composition of various mucin secreting cells using histochemical stains in rats fed on a high calorie diet (HCD) treated with antiretroviral therapy (ART). Wistar rats (N = 24) were divided into a lean control group (C/ART−), high calorie diet group (C/HCD+), ART group (C/ART+) and HCD and ART group (HCD+/ART+). The body of the stomach as well as the colon were stained with Alcian Blue Periodic Schiff (ABPAS) to distinguish between neutral and acidic mucins and Alcian Blue Aldehyde Fuschin (ABAF) to distinguish between sialo-and sulphomucins. An increase of the total gastric mucous cells was observed in the HCD+/ART+ group compared to the C/ART− group using both ABPAS and ABAF. A decrease of neutral cells in the distal part of the colonic crypts in the C/HCD+ and C/ART+ groups compared to the C/ART− group were observed. Mixed goblet cells in the colonic crypts of the C/ART− and HCD+/ART+ groups were decreased in comparison to the C/ART+ group. The study showed that the total mean percentage of mucous cells in the stomach as well as the total amount of neutral goblet cells in the colon were most affected by ART and a HCD. These changes in a rat model suggest that the quality of the biofilm may be altered and should be considered when ART is prescribed to obese patients. © 2016 Elsevier GmbH. All rights reserved. 1. Introduction The intestinal biofilm is a viscoelastic layer found in the lumen of the gastrointestinal tract (GIT) and consists of composite micro- bial populations and the secretions of mucin secreting cells (Allen, 1981; Hollander, 1963; Kleessen and Blaut, 2005). Mucins are large carbohydrate-rich glycoproteins (Byrd and Bresalier, 2004) which provide the initial binding site for commensal micro-organisms to form an adhesive layer that ultimately forms microcolonies. The biofilm acts as the first defence against irritants and pathogens in the GIT and facilitates nutrient exchange between the lumen and Abbreviations: ABPAS, alcian blue periodic acid schiff; ABAF, alcian blue aldehyde fuschin; ART, antiretroviral therapy; C, control; EFV, efavirenz; FTC, emtricitabine; HCD, high calorie diet; TDF, tenofovir disoproxil fumarate. ∗ Corresponding author. E-mail address: shk@sun.ac.za (S.H. Kotzé). the mucosa (Kim and Ho, 2010; Kleessen and Blaut, 2005). Using histochemistry, mucins can be classified as neutral or acidic. Fur- thermore, acidic mucins may contain sialic acid (sialomucin) or sulphate groups (sulphomucin) (Filipe, 1979). The distribution of these histologically identifiable mucin secreting cells can indirectly give an indication of the quality of the biofilm in a particular GIT segment as the biofilm is notoriously difficult to visualise using histology (Palestrant et al., 2004). The types of intestinal mucins secreted at a given time in the GIT may vary depending on need and disease present (McGuckin et al., 2011). Neutral mucins are integral in buffering an acidic environment such as the stomach (Cao and Wang, 2009; Petrinec et al., 2005). Sialic acid is essential in the hydroxyl radical ( • OH) scavenging properties of sialomucins whereas sulphomucin secre- tion results in an increased mucus viscosity and therefore tends to thicken the mucous layer (Croix et al., 2011; Ogasawara et al., 2007). A reduction of sulphomucins in relation to sialomucins may http://dx.doi.org/10.1016/j.acthis.2016.11.014 0065-1281/© 2016 Elsevier GmbH. All rights reserved.