原位杂交方法检测白细胞介素1及肿瘤坏死因子α在鼠根尖周炎中的基因表达

Relationships between periapical lesion and IL-1、TNF-α gene expression in rat

目的 通过观察鼠根尖周炎中白细胞介素 1(interleukin 1,IL 1)、肿瘤坏死因子α(tumornecrosisfactor α ,TNF α)的基因表达 ,了解它们在根尖周炎致病机制中的作用。方法 建立大鼠根尖周炎动物模型 ,于术后 1、2、3、4周取下颌骨组织 ,摄X线牙片、制作石蜡切片 ;用原位杂交技术测定IL 1α、IL 1β及TNF αmRNA在根尖周炎组织中的表达 ,进行半定量分析 ,并将其与根尖阴影面积作相关分析。结果 术后 1～ 3周根尖周炎组织中IL 1α、IL 1β、TNF α表达量逐渐增高 ,至第 3周阳性细胞数达峰值 ,呈时间依赖关系 ,4周后有所下降 ;IL 1α和TNF α表达量远高于IL 1β表达量 ;并且IL 1α和TNF αmRNA阳性表达细胞数与根尖阴影面积呈显著正相关关系 (IL 1α:r =0 875 ,P <0 0 0 1;TNF α:r=0 85 8,P <0 0 0 1) ,IL 1α和TNF α间亦呈显著正相关 (r =0 96 9,P <0 0 0 1)。阳性细胞类型为多形核粒细胞、巨噬细胞、淋巴细胞、浆细胞、成纤维细胞及血管内皮细胞等。结论 IL 1α和TNF α是鼠根尖周炎中的主要细胞因子 。

Objective To understand the effects of the IL-1、 TNF-α cytokines on the pathogenesis of periapical lesions by investigating its gene expression in rat. Methods The model was established by surgically exposing mandibular molar teeth and left open to permit infection from the oral environment. The SD rats were killed at 1、 2、 3、 4 weeks and mandibular molar teeth X-ray were taken.In situ hybridization was used to test IL-1α、IL-1β、TNF-α mRNA expression in periapical area and the kinds of positive cells were identified. Using image analysis system analyzed gene expression semi-quantified. Results IL-1α, IL-1β and TNF-α mRNA were all expressed beginning at 1 week, peaked at 3 weeks, and declined somewhat at 4weeks, but IL-1β mRNA was expressed at much lower levels with the same kinetics(P<0.01). Most of the staining occurred in areas that had heavy inflammatory infiltrate, fibroblasts, or endothelial cells. There was a statistically significant correlations between the area of periapical lesion and the number of positively stained cells for IL-1α and for TNF-α(IL-1α: r=0.875, P<0.001; TNF-α: r=0.858, P<0.001), and between the number of positive cells for IL-1α and that of for TNF-α(r=0.969, P<0.001).Conclusions IL-1α and TNF-α genes are highly expressed in developing periapical lesions in rat, which supports the hypothesis that these two cytokines play a key role in pulpal and periapical pathogenesis, including the concomitant bone destruction.