GaAlAs Laser Irradiation Induces Active Tertiary Dentin Formation after Pulpal Apoptosis and Cell Proliferation in Rat Molars
GaAlAs Laser Irradiation Induces Active Tertiary Dentin Formation after Pulpal Apoptosis and Cell Proliferation in Rat Molars
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DOI：
10.1016/j.joen.2011.05.020
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发表时间：
2011-08-01
影响因子：
4.2
通讯作者：
Ohshima, Hayato
中科院分区：
文献类型：
--
作者：
Shigetani, Yoshimi;Sasa, Natsuki;Ohshima, Hayato
引言：本研究旨在阐明牙髓对砷化镓铝（GaAlAs）激光照射的反应。研究方法：以0.5或1.5W的输出功率照射8周龄大鼠的上颌第一磨牙180秒，并在0至14天的间隔收集样品。除溴脱氧尿苷（BrdU）标记的细胞增殖试验和脱氧核苷酸转移酶脱氧尿苷三磷酸缺口末端标记（TUNEL）的细胞凋亡试验外，对脱钙石蜡切片进行热休克蛋白（HSP）-25和巢蛋白的免疫组织化学处理。结果如下：强烈的HSP-25和nestin免疫反应性在成牙本质细胞层被削弱后立即0.5-W照射，并在第1天恢复，导致轻微的三级牙本质形成的第14天。相反，1.5-W照射立即引起HSP-25和nestin免疫反应性的损失在成牙本质细胞层。在第1天，大量TUNEL阳性细胞出现在变性区，周围是强烈的HSP-25免疫反应。BrdU阳性细胞发生在强烈的HSP-25免疫阳性区域在第2天至第5天，而TUNEL阳性细胞的数量逐渐减少到第5天。HSP-25和巢蛋白阳性的成牙本质细胞样细胞排列沿着牙髓牙本质边界的第7天，导致显着的三级牙本质形成的第14天。结论：GaAlAs激光照射后的输出能量确定牙髓愈合模式;较高的能量诱导受影响的牙髓包括成牙本质细胞的凋亡，随后在退变组织周围强烈的HSP-25免疫反应区域中活跃的细胞增殖，导致丰富的三级牙本质形成。因此，最佳的GaAlAs激光照射引起有意的第三牙本质形成的牙髓。（J Endod 2011;37：1086-1091）
Introduction: This study aimed to clarify pulpal responses to gallium-aluminum-arsenide (GaAlAs) laser irradiation. Methods: Maxillary first molars of 8-week-old rats were irradiated at an output power of 0.5 or 1.5 W for 180 seconds, and the samples were collected at intervals of 0 to 14 days. The demineralized paraffin sections were processed for immunohistochemistry for heat-shock protein (HSP)-25 and nestin in addition to cell proliferation assay using bromodeoxyuridine (BrdU) labeling and apoptosis assay using deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (TUNEL). Results: Intense HSP-25 and nestin immunoreactivities in the odontoblast layer were weakened immediately after 0.5-W irradiation and recovered on day 1, resulting in slight tertiary dentin formation by day 14. On the contrary, 1.5-W irradiation immediately induced the loss of HSP-25 and nestin-immunoreactivities in the odontoblast layer. On day 1, numerous TUNEL-positive cells appeared in a degenerative zone that was surrounded by intense HSP-25 immunoreactivity. BrdU-positive cells occurred within the intensely HSP-25-immunopositive areas during days 2 through 5, whereas TUNEL-positive cells gradually decreased in number by day 5. HSP-25- and nestin-positive odontoblast-like cells were arranged along the pulp-dentin border by day 7, resulting in remarkable tertiary dentin formation on day 14. Conclusions: The output energy determined pulpal healing patterns after GaAlAs laser irradiation; the higher energy induced the apoptosis in the affected dental pulp including odontoblasts followed by active cell proliferation in the intense HSP-25-immunoreactive areas surrounding the degenerative tissue, resulting in abundant tertiary dentin formation. Thus, the optimal GaAlAs laser irradiation elicited intentional tertiary dentin formation in the dental pulp. (J Endod 2011;37:1086-1091)