Evaluation of a mouse odontoma model and elucidation of the developmental mechanisms of odontoma

多聚(ADP-核糖)聚合酶(PARP1)通过转录调控在细胞死亡和细胞分化中发挥作用。在本研究中，对PARP1-/-和遗传背景为ICR/129Sv的野生型PARP1+/+&gt；小鼠的包括门牙在内的脱钙下颌骨进行了组织学分析。对10只雄性PARP1^&lt；-/-&gt；小鼠和13只雄性PARP1^；+/+&gt；小鼠进行了分析。在PARP1^&lt；-/-&gt；小鼠的所有样本中，牙本质表现出显著的增殖，并在牙髓腔内观察到不规则排列的成牙本质细胞。相比之下，来自PARP1^；+/+&gt；小鼠的样本中的成牙本质细胞在牙髓一侧规则地排列，没有观察到釉质的异常。为阐明PARP1在人牙本质瘤发生发展中的作用，对7例复合型和6例复合型人牙本质瘤标本进行…免疫组织化学分析更多的是因为他们的PARP1的表达。结果表明，PARP1在牙胚样组织、减少的釉质上皮、未成熟牙本质和未成熟釉质中均有表达。此外，在成牙本质细胞和与成釉细胞相对应的上皮成分中也检测到了它的表达。这些发现表明PARP1有助于构成牙瘤的细胞的分化。此外，PARP1表达在无核的幽灵细胞的胞浆中。细胞凋亡过程中产生的角蛋白18裂解部位产生的M30CytoDEATH抗体对这些幽灵细胞的胞浆也有很强的免疫染色。由于幽灵细胞被认为是一种积聚硬角蛋白的退行性细胞，而且似乎已经发生了一些早期的凋亡事件，这些观察表明，PARP1在凋亡的幽灵细胞中的表达有助于牙瘤中这些细胞的形成。较少

Poly (ADP-ribose) polymerase (Parp1) is known to play roles in cell death and cell differentiation through transcriptional control. In the present study, decalcified mandibles, including the incisors, from Parp1-/- and wild-type Parp1^<+/+> mice with a genetic background of ICR/129Sv maintained on a basal diet for 2 years were subjected to histological analyses. A total of 10 samples from male Parp1^<-/-> mice and 13 samples from male Parp1^<+/+> mice were analyzed. In all samples from the Parp1^<-/-> mice, the dentin showed remarkable proliferation and irregularly lined odontoblasts were observed on the inside of the dental pulp cavity. In contrast, the odontoblasts in the samples from the Parp1^<+/+> mice were regularly lined up on the side of the dental pulp and no abnormalities of the enamel were observed. To elucidate the involvement of PARP1 in the development of human odontoma, samples obtained from 7 complex type and 6 compound type human odontoma cases were analyzed immunohist … More ochemically for their expressions of PARP1. The results revealed that PARP1 was expressed in tooth germ-like tissue, reduced enamel epithelium, immature dentin and immature enamel in the odontomas. Moreover, its expression was detected in odontoblasts and the epithelial component corresponding to ameloblasts. These findings indicate that PARP1 contributes to the differentiation of the cells that constitute odontomas. In addition, PARP1 was expressed in the cytoplasm of ghost cells that did not possess a nucleus. The cytoplasm of these ghost cells was also strongly immunostained by the M30CytoDEATH antibody raised against the cleavage site of cytokeratin 18 produced during the process of apoptosis. Since ghost cells are considered to represent a type of degenerative cells that accumulate hard keratins, and some early apoptosis events seem to have occurred, these observations indicate that PARP1 expression in ghost cells undergoing apoptosis contributed to the formation of these cells in odontomas. Less