糖尿病对小型猪牙龈组织形态及DNA甲基化的影响研究

Changes of morphology and DNA methylation of gingival tissues in mini-pigs with diabetes

目的研究糖尿病对小型猪牙龈组织形态及其DNA甲基化的影响。方法选取广西巴马小型猪6只,均分为糖尿病组和非糖尿病组,糖尿病组通过静脉注射链脲佐菌素(STZ)建立糖尿病小型猪模型,非糖尿病组小型猪注射等量生理盐水。注射STZ和生理盐水后3个月处死所有小型猪,分析两组胰腺、肾和牙龈组织的组织学改变,并对牙龈组织进行全基因组DNA甲基化水平测定。结果注射STZ后3个月,糖尿病组成功建立糖尿病小型猪模型,组织学检测显示糖尿病组胰腺组织中胰岛数量减少、形态萎缩,胰腺内β细胞减少;其肾组织内的肾小管上皮细胞空泡变性;牙龈组织上皮钉突变短、变少,牙龈内血管数量减少,与非糖尿病组比较,差异均有统计学意义(t值分别为3.35、13.84、2.90,均P<0.05)。糖尿病组牙龈组织中DNA甲基化水平发生显著改变,其中599个基因出现上调,564个基因出现下调。在糖尿病组牙龈组织中,免疫调节相关基因(如补体成分4结合蛋白)及血管生成相关基因(如血管紧张素转换酶、血管紧张素转换酶2和人血管生成素样蛋白2)的DNA甲基化水平显著上调,而炎症相关基因(如肿瘤坏死因子α、白细胞介素6和C-C基序趋化因子配体22)的DNA甲基化水平则显著下调,与非糖尿病组比较,差异均有统计学意义(均P<0.05)。结论糖尿病增加了牙周炎的易感性,其可能通过影响免疫炎症相关基因的DNA甲基化促进牙龈组织炎症的发生。

Objective To investigate the effects of diabetes on gingival tissue in terms of DNA methylation and morphology changes using a mini-pig model.Methods Six Guangxi BA-MA Mini-Pigs were randomly divided into diabetes mellitus group and non-diabetes mellitus group.Diabetic mini-pig models were established by intravenous instillation of streptozotocin(STZ);non-diabetes mellitus group were injected the same amount of normal saline.After 3 months,the animals were sacrificed;pancreatic and renal tissues were collected for histological examination,and gingival tissue for histology and DNA methylation analysis.Results Mini-pig diabetes models were successful created,which were characterized by a higher glucose level and the classic histology changes of diabetes in pancreas such as the reduction and atrophy of the islets.Also,compared with the non-diabetes mellitus group,there was vacuolization in the renal tubular epithelial cells,morphological changes in the gingival tissue and significant reduction in the number of blood vessels in the gingiva in the diabetic group(t=3.35,13.84,2.90,and P<0.05).Diabetes induced significant changes of DNA methylation at gingival tissues,with upregulation in 599 genes and downregulation in 564 genes.The diabetes significantly upregulated the DNA methylation of immune-related genes such as C4BPA,while downregulated the DNA methylation of inflammation-related genes such as TNF-αand IL-6,which are closely related with periodontitis.Also,there was a significant methylation upregulation of angiogenesis-related genes,angiotensin converting enzyme(P<0.05).Conclusion Diabetes increases the susceptibility to periodontitis,which could promote inflammation of gingival tissues by affecting DNA methylation of genes involved in immune inflammation.