丝蛋白复合骨形态发生蛋白2在大鼠炎性牙髓愈合中的作用

Wound healing effects of silk fibroin-bone morphogenetic protein-2 scaffolds on inflammatory pulp in rats

目的：探讨将丝蛋白复合骨形态发生蛋白2（bone morphogenetic protein 2,BMP-2）作为盖髓剂,治疗由脂多糖（lipopolysaccharide,LPS）引起的大鼠炎性牙髓的效果。方法：30只雄性Wistar大鼠,随机分为5组：（1）未手术正常对照组;（2）空白对照组（无盖髓剂）;（3）氢氧化钙组;（4）静电纺丝丝蛋白组（简称丝蛋白组）;（5）静电纺丝丝蛋白复合BMP-2组（简称丝蛋白复合BMP-2组）。将第2∽5组双侧上颌第一磨牙开髓并放置LPS,不使用盖髓剂或使用相应盖髓剂,然后封闭开髓孔。所有组于术后第3、7、14天制作石蜡切片,行HE染色及CD14免疫组织化学染色,采用image-pro plus（IPP）软件测量免疫组织化学染色的光密度（D）值。结果：HE染色结果显示丝蛋白复合BMP-2组在各盖髓组中,术后7及14 d炎性细胞分级最低,其次是氢氧化钙组及丝蛋白组,空白对照组最高;修复性牙本质形成分级的高低顺序则相反。CD14免疫组织化学染色结果显示术后3及7 d,使用盖髓剂的3个组之间D值差异无统计学意义,但均显著低于空白对照组;14 d时丝蛋白复合BMP-2组D值（0.145±0.011）显著低于空白对照（0.287±0.019）、氢氧化钙（0.170±0.017）、丝蛋白（0.175±0.018）3个组（P〈0.05）。结论：丝蛋白复合BMP-2应用于炎性牙髓的盖髓,能减轻炎症,诱导修复性牙本质的形成,提高对炎性牙髓的治疗效果。

Objective： To identify the healing effect of electrospun silk fibroin-BMP-2 as a biologic pulp capping agent to inflammatory pulp in rat caused by lipopolysaccharide（ LPS）. Methods： A total of 30 healthy adult male Wistar rats were randomly divided into five groups：（ 1） normal control group without operation;（ 2） blank control group without capping agents;（ 3） calcium hydroxide capping group;（ 4）electrospun silk fibroin capping group;（ 5） electrospun silk fibroin-BMP-2 capping group. Bilateral upper first molars of each rat in group 2- 5 were drilled to expose the pulp to LPS which was used to establish a model of inflammatory pulp. The exposed pulp was capped with different capping agents or without capping agents. Then the hole was sealed. The animals were sacrificed on days 3,7,and 14 post-operation and histological analysis was carried out,including HE stain and CD14 immunohistochemical stain.Results： On day 7 and 14,the lowest inflammatory reaction score in HE stain among pulp capping groups was that of silk fibroin-BMP-2 group. The next were calcium hydroxide group and silk fibroin group. That of blank control group was the highest. The ranking of reparative dentine scores of those groups was just reversed. The D values of immunohistochemical stain of CD14 were not significantly different in groups applied pulp capping agents but significantly lower than blank control group on days 3 and 7. However,the D value of silk fibroin-BMP-2 group（ 0. 145 ± 0. 011） was significantly lower than blank control group（ 0. 287 ± 0. 019）,calcium hydroxide group（ 0. 170 ± 0. 017） and silk fibroin group（ 0. 175 ±0. 018） on day 14. Conclusion： Electrospun silk fibroin compounded with BMP-2 promoted wound healing of exposed pulp and had better potential to stimulate formation of reparative dentine to establish a suitable environment for pulp recovery.