α7烟碱型乙酰胆碱受体基因敲除小鼠牙髓炎模型的构建

Construction of the dental pulpitis model of α7 nAChR gene knock out mice

目的:构建α7烟碱型乙酰胆碱受体(α7 nicotine acetylcholine receptor,α7 n AChR)基因敲除小鼠牙髓炎模型,为研究α7 nAChR在牙髓炎发生发展过程中的作用机制提供实验模型。方法:取16只α7 n AChR基因敲除(knock out,KO)小鼠和16只野生型(wide type,WT)C57BL/6鼠的上颌第一磨牙的牙髓暴露法建立牙髓炎模型,分别在牙髓暴露后1、3、7 d处死小鼠,HE染色、免疫组化检测牙髓组织NOD样受体蛋白3(NOD-like receptor protein 3,NLRP3)表达情况。结果:HE染色结果显示牙髓暴露后1 d,α7 n AChR KO鼠及WT鼠的穿髓孔周围血管充血、组织水肿;牙髓暴露后3 d,炎症细胞聚集,α7 n AChR KO鼠炎症细胞聚集已达冠髓底部,WT鼠的炎症细胞主要聚集在穿髓孔周围的牙髓组织中;牙髓暴露后7 d,α7 nAChR KO鼠的牙髓炎症细胞浸润至根部牙髓,而WT鼠的牙髓炎症细胞仍然主要聚集于冠髓底部。免疫组化染色结果显示,牙髓暴露后,α7 n AChR KO鼠牙髓NLRP3表达高于WT鼠,差异有统计学意义(P <0.05)。结论:成功建立了α7 n AChR基因敲除鼠的牙髓炎模型,而且α7nAChR基因敲除鼠牙髓炎症浸润明显快于WT小鼠。

Objective:The dental pulpitis model of α7 nAChR gene knockout mice was established to provide an experimental model for studying the mechanism of α7 nAChR in the occurrence and development of dental pulpitis. Methods:Sixteen α7 nAChR knockout mice(knock out,KO)and 16 wild type(wild type,WT)in C57 BL/6 were selected,and a hole was drilled on the maxillary first molars to expose dental pulp to constructed dental pulpitis model. The mice were sacrificed on 1 day,3 days,7 days after operation respectively. HE staining and immunohistochemistry were carried out for detecting NOD-like receptor protein 3(NLRP3). Results:HE staining showed blood congestion and tissue edema around the medullary foramen in α7 n AChR KO mice and WT mice at 1 day after medullary cavity exposure. On 3 days after the exposure of the dental pulp cavity,the inflammatory cells were aggregated,reached to the bottom of the crown pulp in α7 nAChR KO mice,while were mainly around the perforationin the pulp tissue in WT mice. On 7 days,pulpitis cells of α7 nAChR KO mice were infiltrated into root pulp,while inflammatory pulp cells of WT mice were still concentrated mainly in the crown pulp. The expression of NLRP3 in pulpitis of α7 nAChR KO mice was significantly higher than that of WT mice by immunohistochemical staining(P < 0.05). Conclusion:The pulpitis model of α7 n AChR gene knockout mice was successfully constructed,and the pulpitis infiltration of α7 nAChR gene knockout mice was significantly faster than that of WT mice.