根尖周炎模型小鼠白细胞介素24的表达

Expression of interleukin-24 in a mouse model of periapical periodontitis

背景:根尖周炎是一种由混合细菌感染所引起的根尖周组织炎症性疾病,可伴根尖周骨质破坏。研究表明,白细胞介素24作为一种多效性免疫调节因子在炎症反应过程中发挥重要作用并影响骨稳态。目的:通过小鼠体内实验研究白细胞介素24在根尖周炎病变过程中的表达情况。方法:在小鼠口内构建诱发性动物模型以模拟人根尖周炎病程发展。选取6周龄C57BL/6雌性小鼠25只,按随机原则平均分为5组。对实验组小鼠双侧下颌第1磨牙全麻下开髓,之后分别暴露于口腔7,14,21,28 d,设为1周组、2周组、3周组、4周组,对照组不做开髓处理,设为0周组。于各时间点麻醉后分离下颌骨组织。利用苏木精-伊红染色法观察根尖周病损部位的组织病理变化,利用IHC染色及RT-PCR检测白细胞介素24在小鼠根尖周炎病损组织中的表达与变化。实验方案经大连医科大学口腔医学院动物实验伦理委员会批准。结果与结论:①苏木精-伊红结果显示:0周组正常根尖周范围未见明显炎症反应;各实验组根尖周区域可见炎性细胞浸润范围不断扩大,根尖周组织不断破坏,表明小鼠根尖周炎动物模型建立成功;②IHC结果显示:0周组正常根尖周围组织中几乎无白细胞介素24表达;各实验组根尖周区域白细胞介素24表达量较0周组明显增高(P<0.05),且在2周组呈现表达高峰;③RT-PCR结果显示:各实验组根尖区组织中白细胞介素24的mRNA表达水平均较0周组增高(P<0.05),且在2周达到峰值;④结果说明,在诱发性根尖周炎动物模型中,白细胞介素24表达增高且随病变发展有一定趋势,提示其参与了根尖周炎的发生发展,与根尖周炎的炎症进展相关。

BACKGROUND:Apical periodontitis,often accompanied by periapical bone destruction,is an inflammatory disease of the periapical tissue caused by mixed bacterial infections.Studies have shown that interleukin-24 plays an important role in inflammatory response and affects bone homeostasis as a pleiotropic immune regulator.OBJECTIVE:To explore the expression of interleukin-24 during periapical periodontitis in mice.METHODS:An induced animal model was constructed in mice to simulate the progression of human apical periodontitis.Twenty-five C57BL/6 female mice at 6 weeks of age were randomly divided into five groups.Mice in the experimental group were anesthetized and the pulps of both mandibular first molars were exposed to the oral cavity for 7,14,21,and 28 days,named 1-,2-,3-,and 4-week groups.The control group was given no treatments as 0-week group.Mandibular tissues were separated in each group after anesthesia,and then were fixed,decalcified and made into frozen slices of the molar region.Hematoxylin-eosin staining was used to observe the histopathological changes of periapical lesions.Immunohistochemistry staining and RT-PCR were used to detect the expression and changes of interleukin-24 in periapical lesions of mice.The study was approved by the Animal Ethics Committee of Dalian Medical University School of Stomatology.RESULTS AND CONCLUSION:The results of hematoxylin-eosin staining showed that no obvious inflammatory response was observed in the normal periapical region of the 0-week group;the inflammatory cell infiltration area was continuously expanded and the periapical tissue was continuously destroyed in each experimental group,indicating that mouse model of periapical periodontitis was successfully established.The results of immunohistochemistry staining showed that there was almost no interleukin-24 expression in the 0-week group;the expression of interleukin-24 in the periapical region of each experimental group was significantly higher than that in the 0-week group(P<0.05),and showed a peak expression in the 2-week group.The results of RT-PCR showed that the mRNA level of interleukin-24 in each experimental group was higher than that in the 0-week group(P<0.05),and peaked at 2 weeks.Overall,our findings indicate that in the animal model of periapical periodontitis,the expression of interleukin-24 increases with a certain trend in the development of periapical lesions,suggesting that it may be involved in the progression of inflammation related to periapical periodontitis.