Department of Periodontology, Faculty of Dentistry, Tokat Gaziosmanpasa University, Tokat, Turkey.
Department of Histology and Embryology, Faculty of Medicine, Tokat Gaziosmanpasa University, Tokat, Turkey.
J Periodontal Res. 2020 Oct;55(5):676-685. doi: 10.1111/jre.12754. Epub 2020 Apr 26.
Periodontitis is the chronic destructive disease of the periodontium, which causes severe inflammation in the tissues. Cinnamic acid as an unsaturated carboxylic acid might prevent inflammation and periodontal destruction. The present study aimed to evaluate the effects of cinnamic acid in two different forms as free cinnamic acid and cinnamic acid liposome on experimental periodontitis in Wistar rats.
Thirty-two female rats were used in the present study. Four main groups were created as follows: C: control group; P: periodontitis group; C-P: free cinnamic acid-administered periodontitis group; and CL-P: cinnamic acid liposome applied group. Periodontitis was induced via ligating 4-0 silk sutures around lower first molar teeth on both right and left mandibles. The study duration was 30 days, and the ligatures were removed from half of the rats in the periodontitis-induced groups. The other half carried the ligatures throughout 30 days, and all rats were euthanized at 30th day. Mandibles were removed and evaluated via stereomicroscope and underwent histological procedures. Inflammatory cell counts, osteoblast, and osteoclast cell counts were determined in hematoxylin-eosin-stained slides, and peroxisome proliferator-activated receptor (PPAR)-γ, cyclooxygenase (COX)-2, receptor activator of nuclear factor κ-B (RANKL), and osteoprotegerin (OPG) expressions were evaluated by immunohistochemistry.
Control group had the lowest bone loss, and periodontitis group which kept ligatures had the highest bone loss compared to the other groups. Ligature removal provided significant improvement in bone measurements. Cinnamic acid groups also showed lower bone loss compared to the periodontitis group. The inflammatory cell and osteoclast counts were also higher in the periodontitis group, and both applications of cinnamic acid decreased these values. Osteoblast cells were the lowest in the periodontitis group, and cinnamic acid increased these counts. PPAR-γ and COX-2 levels were higher in the periodontitis group, and cinnamic acid decreased these levels but not to a significant level except for the cinnamic acid liposome ligature removal group, which had significantly lower values in the PPAR-γ and COX-2. OPG levels were lower in the periodontitis group compared to the other groups. Cinnamic acid significantly decreased RANKL and increased OPG levels.
Periodontitis caused increased inflammation and bone destruction accompanied by increased PPAR-γ, COX-2, and RANKL levels and osteoclast counts. Cinnamic acid decreased osteoclast counts and inflammation and increased osteoblast counts and OPG expression in the present animal model of periodontitis.
牙周炎是一种慢性破坏性牙周疾病，会导致组织严重炎症。肉桂酸作为一种不饱和羧酸，可能具有抗炎和防止牙周破坏的作用。本研究旨在评估游离肉桂酸和肉桂酸脂质体两种不同形式的肉桂酸对 Wistar 大鼠实验性牙周炎的影响。
本研究使用了 32 只雌性大鼠。创建了以下 4 个主要组：C：对照组；P：牙周炎组；C-P：游离肉桂酸给药牙周炎组；CL-P：肉桂酸脂质体应用组。通过在左右下颌骨的下第一磨牙周围结扎 4-0 丝线来诱导牙周炎。研究持续 30 天，在牙周炎诱导组的一半大鼠中去除结扎线。另一半大鼠在 30 天内一直保留结扎线，所有大鼠均在第 30 天处死。取出下颌骨，通过立体显微镜进行评估，并进行组织学处理。在苏木精-伊红染色的载玻片上测定炎症细胞计数、成骨细胞和破骨细胞计数，通过免疫组织化学法评估过氧化物酶体增殖物激活受体（PPAR）-γ、环氧化酶（COX）-2、核因子 κ-B 受体激活剂（RANKL）和骨保护素（OPG）的表达。
对照组的骨损失最低，而保留结扎线的牙周炎组与其他组相比骨损失最高。结扎线去除提供了显著的骨测量改善。肉桂酸组的骨损失也低于牙周炎组。牙周炎组的炎症细胞和破骨细胞计数较高，而两种肉桂酸的应用均降低了这些值。牙周炎组的成骨细胞计数最低，而肉桂酸增加了这些计数。PPAR-γ 和 COX-2 水平在牙周炎组中较高，而肉桂酸降低了这些水平，但除了肉桂酸脂质体结扎去除组外，这些水平没有显著降低，该组的 PPAR-γ 和 COX-2 水平显著降低。OPG 水平在牙周炎组中低于其他组。肉桂酸显著降低了 RANKL 并增加了 OPG 水平。
牙周炎导致炎症和骨破坏增加，同时伴有 PPAR-γ、COX-2 和 RANKL 水平以及破骨细胞计数增加。在本牙周炎动物模型中，肉桂酸降低了破骨细胞计数和炎症，增加了成骨细胞计数和 OPG 表达。
