APOPTOSIS AND HETEROPHAGY OF MEDIAL EDGE EPITHELIAL-CELLS OF THE SECONDARY PALATINE SHELVES DURING FUSION
APOPTOSIS AND HETEROPHAGY OF MEDIAL EDGE EPITHELIAL-CELLS OF THE SECONDARY PALATINE SHELVES DURING FUSION
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DOI：
10.1679/aohc.58.191
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发表时间：
1995-06-01
影响因子：
--
通讯作者：
UCHIYAMA, Y
中科院分区：
文献类型：
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作者：
TANIGUCHI, K;SATO, N;UCHIYAMA, Y
最近的体内和体外研究表明，覆盖腭侧架的内侧缘上皮（Medial Edge Epithelial，MEE）细胞不会发生细胞死亡，而是迁移到口腔和鼻腔上皮或转化为间充质细胞。因此，我们通过原位3'缺口末端标记dUTP（TUNEL）、电子显微镜和免疫组织化学方法，重新研究了大鼠胚胎腭融合过程中腭突细胞的命运。TUNEL染色显示接触前即刻内侧缘上皮、上皮缝与鼻或口腔上皮之间形成的上皮三角形、上皮珠和上皮附近的间充质组织中有阳性细胞核。然而，这些TUNEL阳性细胞很少出现在上皮缝。电子显微镜检查显示，在融合的上皮细胞中有核染色质浓缩和细胞皱缩，以及凋亡小体;这些细胞通常含有凋亡小体样结构作为异噬体。通过使用激光扫描显微镜进行双重染色，TUNEL阳性细胞核仅与溶酶体半胱氨酸蛋白酶、组织蛋白酶B或L共定位于上皮细胞和邻近上皮的间充质细胞中。这些结果表明，在腭形成过程中，即使它们迁移到上皮三角或转化为间充质细胞，腭上皮细胞也会发生凋亡。此外，凋亡小体和细胞碎片被邻近的间充质细胞或间充质细胞吞噬，并被溶酶体酶消化。
Recent in vivo and in vitro studies have suggested that medial edge epithelial (MEE) cells covering the lateral palatine shelves do not undergo cell death, but migrate into the oral and nasal epithelium or transform into mesenchymal cells. We, therefore, reexamined the fate of MEE cells during palatal fusion in rat embryos by in situ 3' nick end labeling of dUTP (TUNEL), electron microscopy, and immunohisto/cytochemistry. TUNEL staining revealed positive nuclei in the medial edge epithelium immediately prior to contact, in epithelial triangles formed between the epithelial seam and nasal or oral epithelium, in epithelial pearls, and in mesenchymal tissue near the epithelium. However, these TUNEL-positive cells were rarely present in the epithelial seam. Electron microscopy revealed MEE cells showing nuclear chromatin condensation and cell shrinkage, and apoptotic bodies in the fusing epithelium; these often contained apoptotic body-like structures as heterophagosomes. By double staining using a laser scanning microscope, TUNEL-positive nuclei mere co-localized with lysosomal cysteine proteinases, cathepsin B or L in MEE and mesenchymal cells adjacent to the epithelium. These results suggest that MEE cells undergo apoptosis during the palatal formation, even though they migrate into epithelial triangles or transform into mesenchymal cells. Moreover, apoptotic bodies and cellular debris were phagocytosed by adjacent MEE cells or mesenchymal cells and digested by lysosomal enzymes.