Nel-like molecule-1 (NELL-1) is a novel highly specific growth factor that can induce osteoblast differentiation and bone formation as well as odontoblast differentiation. Recent studies have suggested that NELL-1 can synergistically increase bone formation and regeneration with bone morphogenetic protein 2 (BMP2) and inhibit adverse effects induced by BMP2. This study aimed to evaluate the combined effects of NELL-1 and BMP2 on rat pulp repair. The experiment used healthy non-carious maxillary first molars from 60 Wistar rats. Exposed pulps were capped with NELL-1 plus BMP2, NELL-1 alone, and BMP2 alone, and each was absorbed onto a sterile collagen sponge. In the control samples, the collagen sponge alone and Dycal were used as capping agents. After l, 2 and 4 weeks, the rats were sacrificed. The formation of reparative dentin, as well the situation of pulp repair, was detected by hematoxylin-eosin (HE) staining; moreover, the expression of dentin specific protein-dentin sialophosphoprotein (DSPP) and the pro-inflammatory cytokines interleukin-6 (IL6) and interleukin-8 (IL8) was detected by immunohistochemical staining. Quantitative real-time PCR experiment was used to investigate the mRNA levels of IL6 and IL8. The results showed that pulp capping with NELL-1 plus BMP2 in rats had superior ability in inducing reparative dentin formation with dentin tubules and in reducing the inflammatory cell response compared with the other groups. These findings suggested that combined use of NELL-1 and BMP2 could positively regulate pulp repair.

中文翻译：

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Nel样分子1和骨形态发生蛋白2组合对大鼠牙髓修复的影响。

Nel样分子1（NELL-1）是一种新型的高特异性生长因子，可以诱导成骨细胞分化，骨形成以及成牙本质细胞分化。最近的研究表明，NELL-1可以与骨形态发生蛋白2（BMP2）协同增加骨的形成和再生，并抑制BMP2诱导的不良反应。这项研究旨在评估NELL-1和BMP2对大鼠牙髓修复的综合作用。该实验使用了60只Wistar大鼠的健康非龋齿上颌第一磨牙。裸露的牙髓用NELL-1加BMP2，单独的NELL-1和单独的BMP2覆盖，然后分别吸收到无菌胶原海绵上。在对照样品中，单独的胶原蛋白海绵和Dycal被用作封端剂。在1、2和4周后，处死大鼠。修复性牙本质的形成 苏木精-伊红（HE）染色检测牙髓修复情况。免疫组织化学染色检测牙本质特异性蛋白-牙本质唾液磷蛋白（DSPP）和促炎细胞因子白细胞介素6（IL6）和白细胞介素8（IL8）的表达。实时定量PCR实验用于研究IL6和IL8的mRNA水平。结果显示，与其他组相比，用NELL-1加BMP2进行大鼠牙髓封闭具有诱导牙本质小管形成修复性牙本质并降低炎症细胞反应的卓越能力。这些发现表明，NELL-1和BMP2的联合使用可以积极调节牙髓的修复。免疫组织化学染色检测牙本质特异性蛋白-牙本质唾液磷蛋白（DSPP），促炎细胞因子白细胞介素6（IL6）和白细胞介素8（IL8）的表达。实时定量PCR实验用于研究IL6和IL8的mRNA水平。结果显示，与其他组相比，用NELL-1加BMP2进行大鼠牙髓封闭具有诱导牙本质小管形成修复性牙本质并降低炎症细胞反应的卓越能力。这些发现表明，NELL-1和BMP2的联合使用可以积极调节牙髓的修复。免疫组织化学染色检测牙本质特异性蛋白-牙本质唾液磷蛋白（DSPP），促炎细胞因子白细胞介素6（IL6）和白细胞介素8（IL8）的表达。实时定量PCR实验用于研究IL6和IL8的mRNA水平。结果显示，与其他组相比，用NELL-1加BMP2进行大鼠牙髓封闭具有诱导牙本质小管形成修复性牙本质并降低炎症细胞反应的卓越能力。这些发现表明，NELL-1和BMP2的联合使用可以积极调节牙髓的修复。结果显示，与其他组相比，用NELL-1加BMP2进行大鼠牙髓封闭具有诱导牙本质小管形成修复性牙本质并降低炎症细胞反应的卓越能力。这些发现表明，NELL-1和BMP2的联合使用可以积极调节牙髓的修复。结果显示，与其他组相比，用NELL-1加BMP2进行大鼠牙髓封闭具有诱导牙本质小管形成修复性牙本质并降低炎症细胞反应的卓越能力。这些发现表明，NELL-1和BMP2的联合使用可以积极调节牙髓的修复。