Lysosomal Exoglycosidase Profile and Secretory Function in the Salivary Glands of Rats with Streptozotocin-Induced Diabetes

Hindawi Journal of Diabetes Research Volume 2017, Article ID 9850398, 13 pages https://doi.org/10.1155/2017/9850398 Research Article Lysosomal Exoglycosidase Profile and Secretory Function in the Salivary Glands of Rats with Streptozotocin-Induced Diabetes Mateusz Maciejczyk,1 Agnieszka Kossakowska,2 Julita Szulimowska,3 Anna Klimiuk,2 Małgorzata Knaś,4 Halina Car,5 Wiesława Niklińska,6 Jerzy Robert Ładny,7 Adrian Chabowski,1 and Anna Zalewska2 1 Department of Physiology, Medical University of Bialystok, 2c Mickiewicza Street, 15-233 Bialystok, Poland Department of Conservative Dentistry, Medical University of Bialystok, 24a M. Sklodowskiej-Curie Street, 15-274 Bialystok, Poland 3 Department of Pedodontics, Medical University of Bialystok, 24a M. Sklodowskiej-Curie Street, 15-274 Bialystok, Poland 4 Department of Cosmetology, Lomza State University of Applied Sciences, Akademicka 1 str, 18-400 Lomza, Poland 5 Department of Experimental Pharmacology, Medical University of Bialystok, 37 Szpitalna Street, 15-767 Bialystok, Poland 6 Department of Histology and Embryology, Medical University of Bialystok, 13 Waszyngtona Street, Bialystok, Poland 7 Department of Emergency Medicine and Disasters, Medical University of Bialystok, 37 Szpitalna Street, 15-767 Bialystok, Poland 2 Correspondence should be addressed to Mateusz Maciejczyk; Received 28 July 2017; Revised 6 November 2017; Accepted 23 November 2017; Published 31 December 2017 Academic Editor: Janet H. Southerland Copyright © 2017 Mateusz Maciejczyk et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Before this study, there had been no research evaluating the relationship between a lysosomal exoglycosidase profile and secretory function in the salivary glands of rats with streptozotocin- (STZ-) induced type 1 diabetes. In our work, rats were divided into 4 groups of 8 animals each: control groups (C2, C4) and diabetic groups (STZ2, STZ4). The secretory function of salivary glands—nonstimulated and stimulated salivary flow, α-amylase, total protein—and salivary exoglycosidase activities—N-acetylβ-hexosaminidase (HEX, HEX A, and HEX B), β-glucuronidase, α-fucosidase, β-galactosidase, and α-mannosidase—was estimated both in the parotid and submandibular glands of STZ-diabetic and control rats. The study has demonstrated that the activity of most salivary exoglycosidases is significantly higher in the parotid and submandibular glands of STZ-diabetic rats as compared to the healthy controls and that it increases as the disease progresses. Reduced secretory function of diabetic salivary glands was also observed. A significant inverse correlation between HEX B, α-amylase activity, and stimulated salivary flow in diabetic parotid gland has also been shown. Summarizing, STZ-induced diabetes leads to a change in the lysosomal exoglycosidase profile and reduced function of the salivary glands. 1. Introduction Diabetes mellitus (DM) is a group of frequent metabolic disorders characterized by abnormalities in insulin secretion and/or insulin action [1]. The primary clinical manifestation of type 1 diabetes (DM1; OMIM %222,100) is an elevated blood glucose level, which leads to chronic hyperglycemia and subsequent acute and chronic complications, including micro- and macrovascular disease. Metabolic abnormalities in DM1 disturb the function of numerous human organs and systems, including also the salivary glands, which influences oral cavity homeostasis [2, 3]. Many studies have shown that DM1 is strongly associated with oral fungal and bacterial infections, changes in the composition and buffering properties of saliva, higher incidence of lichen planus, and dental caries, as well as periodontal disease [2–4]. However, the pathogenesis of these oral complications is still not fully understood in the context of DM1. The oral cavity is an integral part of the entire human body. It is commonly known that maintenance of the oral homeostasis depends largely on salivary glycoproteins suspended in an aqueous solution of saliva, as well as on 2 the glycoconjugates which are integral parts of the salivary gland structures [5, 6]. Salivary glycoproteins (e.g., immunoglobulins, lactoferrin, and salivary peroxidase system) and glycolipids participate in the interaction between salivary proteins, carbohydrates, oral bacteria, and viruses and thereby play an important role in the oral immune defense mechanisms [7]. Salivary glycoconjugates such as mucins (MUC1, MUC4, MUC5B, MUC7, and MUC19), proline-rich glycoproteins (PRGs), and kallikrein may also ensure the appropriate hydration of the oral mucosa and maintain the proper pH of the stimulated and nonstimulated saliva [8, 9]. Salivary glands produce the intracellular lysosomal enzymes that hydrolysis the oligosaccharide chains of salivary glycoconjugates. This group, known as salivary lysosomal exoglycosidases, includes N-acetyl-β-hexosaminidase (HEX and NAG) and its isoenzymes A (HEX A) and B (HEX B), β-glucuronidase (GLU), α-fucosidase (FUC), βgalactosidase (GAL), and α-mannosidase (MAN) [10]. HEX, the most active salivary exoglycosidase, hydrolyses N-acetylglucosamine (GlcNAc) or N-acetylgalactosamine (GalNAc) from the nonreducing ends of salivary glycoconjugates, whereas salivary GLU hydrolyses the β-glycosidic bonds from the β-glucuronides [10, 11]. Recently, more and more attention has been paid to the determination of salivary lysosomal glycosidases in many oral and systemic diseases [11]. Bierc et al. [12] noted a significant increase in HEX, GLU, and GAL activity in the salivary gland tumor tissue, while Waszkiewicz et al. [13] reported that HEX determination may be a useful marker for salivary dysfunction caused by a single dose of ethanol. Determination of lysosomal exoglycosidases also appears to have a significant diagnostic value in screening and monitoring chronic periodontitis [14], cancer [12, 15], asthma [16], alcohol dependence [17, 18], Lyme borreliosis [19], and rheumatoid arthritis [19, 20], as well as type 1 and type 2 diabetes mellitus [21–23]. It has been demonstrated that increased activity of lysosomal hydrolases in saliva reflects their elevated synthesis/release, which may be associated with lysosomal membrane damage [22, 24]. A positive correlation between the activity of salivary exoglycosidases and the degree of salivary gland dysfunction has also been reported [20, 25]. However, there is no data concerning the lysosomal exoglycosidase profile in the submandibular/parotid gland and/or saliva of DM1 patients as well as in appropriate animal models. Accordingly, the aim of this study was to evaluate the lysosomal exoglycosidase profile and their relationship with salivary amylase activity and salivary flow rate in the salivary glands of rats with streptozotocin- (STZ-) induced type 1 diabetes. 2. Materi (...truncated)