Morphological Features of Dental Tissues in Streptozotocin-Induced Diabetes Mellitus Model

Abstract

The global issue of diabetes mellitus (DM), which is a serious burden faced by the healthcare systems and economies in many countries, has been increasing steadily in the recent decades. The fast pace of DM growth and prevalence, as well as associated complications (macro- and microangiopathy, neuropathy, nephropathy, impaired vision), high economic costs and social damage, high disability and mortality rates entailed by this disease take constant improvement of the respective diagnostics, prevention and treatment approaches. Dental manifestations of DM are diagnosed in most patients and reveal themselves through demineralized hard dental tissues, high intensity of dental caries and its prevalence, as well as the prevalence of periodontal diseases and issues affecting the oral mucosa. Our research included 60 male Wistar stock rats, all divided into two groups: the comparison group with no DM (n=10) and the main group with induced DM (n=50). DM modeling was done by a single intraperitoneal injection of streptozotocin (dosage – 65 mg/kg). The main group lab animals were removed from the experiment on Days 8, 16, 24, 32 and 60 under anesthesia by decapitation. All the histological and morphometric changes observed in the dental tissues were recorded in the ImadgeJ software package using a Leica DM2500 hardware and software set. The studied sections were used to evaluate the thickness of enamel, dentin, predentin, cement, pulp, the dentin tubule diameter, as well as the density of odontoblasts and ameloblasts. On Day 60 into the experiment, the following changes were identified in relation to the hard dental tissues: regarding the enamel − demineralization, disintegration of the interprism substance; deformed enamel prisms; erosion-type defects developing; regarding the dentin − expanded dentin tubules, vacuole dystrophy of odontoblasts, accumulating edematous fluid under the odontoblast layer, deformation and atrophy of odontoblasts; regarding the cement – layer thinning, cementolysis, cavities developing. Quantitative evaluation of rat dental tissues on Day 60, if compared with intact animals, revealed a multidirectional dynamics in the morphometric values. There was a statistically significant (p≤0.05) decrease in the enamel thickness identified (from 31.06±2.17 microns to 18.19±1.36 microns), in predentin (from 25.19±1.48 microns to 20.93±1.16 microns), in cement (from 37.28±2.04 microns to 31.04±1.46 microns), in the dentin tubule diameter (from 1.82±0.14 microns to 1.56±0.13 microns), as well as in the density of odontoblasts (from 7683.24±319.76 units/mm2 to 7312.61±256.19 units/mm2) along with a statistically reliable (p ≤0.05) increase in the thickness of dentin (from 96.54±3.39 microns to 105.11± 3.16 microns), pulp (from 107.43± 4.12 microns to 120.38±5.26 microns), as well as in the ameloblast density (from 6471.39± 272.18 units/mm2 to 6849.06±253.84 units/mm2). The outcomes expand the understanding of the structural changes affecting rat dental tissues at various times through modeling of Type 1 diabetes, as well as results could be used for developing pharmacological correction methods aiming at the reduction of the pathology intensity.