• 대한수의학회지
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• 제37권1호
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• pp.87-101
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• 1997

The development of trachea in fetuses on 60, 90 and 120 days of gestation and neonates of Korean native goats was investigated by microscopy and scanning and transmission electron microscopy. The results were summarized as follows; Light microscopic studies: 1. In the 60-day-old fetuses, the tracheal walls were differentiated and divided into four layers of the mucosa, submucosa, muscle and cartilage, and adventitia. The tracheal epithelium is composed of stratified ciliated columnar epithelium at 60- and 90-day-old fetuses while the epithelium observed at 120-day-old fetuses was pseudostraified ciliated colummar epithelium. 2. In the 90-day-old fetuses, tracheal glands extended into the submucosa and peripheral area of the tracheal cartilage. The blood vessels were observed in the submucosa and adventitia. The elastic and collagenous fibers were observed in the tracheal walls. 3. In the neonates, the tracheal walls consisted of mucosa with well-developed folds, submucosa, tracheal glands, muscle and cartilage, collagenous and elastic fibers, and adventitia, which were more developed than those of 120-day-old fetuses. The tracheal epithelium was developed as that in adults. Scanning electron microscopic studies: 4. In the 60-day-old fetuses, most of tracheal epithelial cells were nonciliated but short microvilli were sporadically observed on the luminal surface. On rare occasions, a few cells have solitary cilium. 5. In the 90-day-old fetuses, the ciliated cells appeared increasingly and cilia elongated longer than those of 60-day-old fetuses. 6. In the 120-day-old fetuses, the nonciliated cells covered with microvilli in dome-shape were barriered by thick carpet of cilia. The nonciliated cells also have many papillary projectons on the apical surface. 7. In the neonates, the nonciliated cells in tracheal epithelium were covered compactly with numerous cilia, and many secretory droplets were found on the cilia. Transmission electron microscopic studies: 8. In the 60-day-old fetuses, nonciliated cells of the tracheal epithelium contain large amounts of glycogen granules in the supernuclear and subnuclear areas meanwhile a few cell organelles were formed. Cilia were well formed along the apical cell membranes of the ciliated cells. Also found in the ciliated cells were basal corpuscles, mitochondria and short chains in granular endoplasmic reticulum(GER). Between the epithelial cells presented were well-defined junctional complex with zonula occludens and desmosomes. The nuclei were variable in size and shape. The more developed nucleoli were observed conspicuosly. 9. In the 90-day-old fetuses, nonciliated cells contained large glycogen granules. Accumulated glycogen granules were observed in the subnuclear and supranuclear portion of the cytoplasm. A few short microvilli were covered with glycocalyx. Ciliated cells contained numerous mitochondria and short chains of GER. 10. In the 120-day-old fetuses, the ciliated cells contained numerous mitochondria, abundant short chains of GER and nucleoli. Nonciliated cells contained some Golgi complex and mitochondria. The cell borders were well-defined and distinct junctional complex with zonula occludens, desmosomes, and interdigitorum. 11. In the neonates, well-developed goblet cells were observed in the tracheal epithelium. Ultrastructures of ciliated and nonciliated cells on the tracheal epithelia were similar in pattern as those in adults.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제32권4호
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• pp.295-307
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• 2006

Styela clava, called non-native tunicate or sea squirt, is habitat which include bays and harbors in Korea and several sites in the sea faced world. We fabricate cellulose membrane nerve conduit (CMNC) from this native sea squirt skin, and evaluate the capacity of promoting peripheral nerve regeneration in the rat sciatic nerve defect model. After processing the pure cellulose membrane from the sea squirt skin as we already published before, CMNC was designed as a non-tubular sheet with 14 mm length and 4 mm width. Total eleven male Spraque-Dawley rats (12 weeks, weighing 250 to 300g) were divided into sham group (n=2), silicone tube grafted control group (n=3) and experimental group (n=6). Each CMNC grafted nerve was evaluated after 4, 8 and 12 weeks in the experimental group, and after 12 weeks, sciatic function was evaluated with sciatic function index (SFI) and gait analysis, and histomorphology of nerve conduit and the innervated tissues of sciatic nerve were all examined using image analyzer and electromicroscopic methods in the all groups. The regenerated axon and nerve sheath were found only in the inner surface of the CMNC after 4 weeks and became more thicker after 8 and 12 weeks. In the TEM study, CMNC grafted group showed more abundant organized myelinated nerve fibers with thickened extracellular matrix than silicone conduit grafted group after 12 weeks. The sciatic function index (SFI) and ankle stance angle (ASA) in the functional evaluation were $-47.2{\pm}3.9$, $35.5^{\circ}{\pm}4.9^{\circ}$ in CMNC grafted group (n=2) and $-80.4{\pm}7.4$, $29.2^{\circ}{\pm}5.3^{\circ}$ in silicone conduit grafted group (n=3), respectively. And the myelinated axon was 41.59% in CMNC group and 9.51% in silicone conduit group to the sham group. The development of a bioactive CMNC to replace autogenous nerve grafts offers a potential and available approach to improved peripheral nerve regeneration. As we already published before, small peptide fragment derived from the basement membrane matrix proteins of squirt skin, which is a kind of anchoring protein composed of glycocalyx, induced the effective axonal regeneration with rapid growth of Schwann cells beneath the inner surface of CMNC. So the possibilities of clinical application as a peripheral nerve regeneration will be able to be suggested.