Messer Jonathan G, Jiron Jessica M, Chen Hung-Yuan, Castillo Evelyn J, Mendieta Calle Jorge L, Reinhard Mary K, Kimmel Donald B, Aguirre J Ignacio
Department of Physiological Sciences, University of Florida, Gainesville, Florida.
Animal Care Services, University of Florida, Gainesville, Florida.
Comp Med. 2017 Feb 1;67(1):43-50.
Marsh rice rats (Oryzomys palustris) fed a pelleted diet high in sucrose and casein have been used as a model for moderate to severe periodontitis. Here we characterize the prevalence, location, and histopathologic features of food-impaction lesions (FIL), a unique type of oral event, in rice rats fed standard pelleted rodent chow from weaning until 34 wk of age. Healthy female rats (n = 90; age, 4 wk) were weaned into groups (n = 10 to 24) and were euthanized at 4, 16, 22, 28, or 34 wk of age. At necropsy, high-resolution photographs of the 4 jaw quadrants were examined by 3 independent observers to determine the presence, number, and location of FIL. In addition, gross periodontitis was scored (scale, 0 to 4), and the hemimaxillar surface area containing FIL was measured. Serial sections of decalcified jaws were assessed histologically. The prevalence of FIL increased with age, and was 0% (baseline), 59.1%, 69.6%, 81.8% and 80.0% in rats at age 4, 16, 22, 28, and 34 wk, respectively. FIL were predominantly located (93.9%) in the maxillary palatal surfaces of the interproximal area between molars 2 and 3 and did not affect mandibular surfaces. The percentage of the hemimaxillar surface area occupied by FIL was 6.83%, 4.82%, 2.88%, and 6.52% in rats at age 16, 22, 28, and 34 wk, respectively. Histopathologic changes in FIL varied from localized gingivitis to larger, localized periodontitis-like lesions. These data indicate that FIL are common in rice rats fed standard rodent chow, are slight to mild in severity, and are localized to specific regions in the oral cavity, thus suggesting they may be a suitable model for local maxillary periodontitis when fed standard rodent chow.
以高蔗糖和酪蛋白颗粒饲料喂养的沼泽稻鼠（Oryzomys palustris）已被用作中度至重度牙周炎的模型。在此，我们描述了从断奶到34周龄一直喂食标准颗粒啮齿动物饲料的稻鼠中食物嵌塞性病变（FIL）（一种独特的口腔病变类型）的患病率、位置和组织病理学特征。将90只健康雌性大鼠（4周龄）断奶并分成若干组（每组10至24只），并在4、16、22、28或34周龄时实施安乐死。尸检时，由3名独立观察者检查4个颌骨象限的高分辨率照片，以确定FIL的存在、数量和位置。此外，对严重牙周炎进行评分（0至4分），并测量包含FIL的半上颌表面积。对脱钙颌骨的连续切片进行组织学评估。FIL的患病率随年龄增加，4周龄、16周龄、22周龄、28周龄和34周龄大鼠的患病率分别为0%（基线）、59.1%、69.6%、81.8%和80.0%。FIL主要位于（93.9%）第2和第3磨牙之间邻间隙的上颌腭面，不累及下颌面。16周龄、22周龄、28周龄和34周龄大鼠中FIL占据的半上颌表面积百分比分别为6.83%、4.82%、2.88%和6.52%。FIL的组织病理学变化从局限性牙龈炎到更大的局限性牙周炎样病变不等。这些数据表明，FIL在喂食标准啮齿动物饲料的稻鼠中很常见，严重程度为轻度至中度，且局限于口腔的特定区域，因此表明当喂食标准啮齿动物饲料时，它们可能是上颌局限性牙周炎的合适模型。
