| 摘要: | 本研究利用光學顯微鏡、掃描式電子顯微鏡及穿透式電子顯微鏡觀察犬鼻淚管，並用血清蛋白金顆粒混合人工淚液當追蹤劑，觀察覆血清金顆粒在犬鼻淚管系統內的流向，藉此探討犬鼻淚管系統吸收淚液成分的功能的機制。
鼻淚引流系統於眼睛的入口為淚點（lacrimal puncta），位於上、下眼瞼緣靠內眥處（medial canthus）。每一淚點都連接淚小管（lacrimal canaliculi），上、下淚小管接合形成淚管（lacrimal duct），在上、下淚小管接合處所形成的膨大部稱為淚囊（lacrimal sac），鼻淚管離開淚囊通過淚骨（lacrimal bone）進入上颌骨內的骨性溝槽（分為骨性垂直部及骨性水平部，約佔鼻淚管長度的1/3），並延伸至膜性鼻腔部(分為近側端鼻腔部和遠側端鼻腔部)之後開口於下鼻道的外側壁。各段犬鼻淚系統結構大致相似，上皮組織屬偽複層柱狀上皮細胞，各段鼻淚系統上皮層厚度不一，以骨性水平部的上皮層最厚（表層柱狀細胞特別長）；上皮表面佈滿短微絨毛（short microvilli），長度約為0.2~0.5m，偶而可見長微絨毛參差其中；纖毛只出現在鼻腔部，以鼻腔部遠側端最多；上皮細胞內有許多淡色、突出表面且核上細胞質內不含黏液性顆粒的杯樣細胞（goblet like cell ）參差在暗細胞中；淡色細胞與暗色細胞的細胞質都含有豐富的粒腺體及肝糖；但，有些上皮細胞頂部含有空泡，有些上皮細胞頂部含均質濃染的黑色顆粒，有些細胞頂部有apical tube。上皮細胞頂部以junctional complex緊密結合，側壁間以指狀細胞質突起（process）併合（interdigitation），形成寬廣的細胞間隙；偶而可見吞噬細胞出現在上皮細胞間。上皮細胞基底膜下的結締組織內含豐富的膠原纖維、血管，且有聚集成束的有髓鞘、無髓鞘神經纖維，mast cell、plasma cell及吞噬細胞亦分佈其中。
將血清蛋白金顆粒（BSA-Au）混合人工淚液由上或下淚小管注入犬鼻淚管，經40分、80分、120分、3小時、4小時和22小時後，將鼻淚系統依淚囊部、骨性垂直部、骨性水平部、鼻腔部近側端和鼻腔部遠側端，製成標本在穿透式電子顯微鏡下觀察。80分鐘始有血清蛋白金顆粒始有出現在上皮細胞核上細胞質的空泡內；2小時後核上和核旁細胞質內的空泡、溶酶體等胞器，都可發現血清蛋白金顆粒。3小時和4小時，血清蛋白金顆粒出現在上皮細胞核上、核旁和核下細胞質內的空泡、溶酶體等胞器，並且在細胞間隙和結締組織內的膠原纖維間、血管壁都可發現血清蛋白金顆粒。但血清蛋白金顆粒在上皮細胞間隙與結締組織內的量，以4小時為最多；22小時，上皮細胞及間隙內完全不見血清蛋白金顆粒。
我們的實驗證實，淚液經鼻淚管系統上皮細胞回流至體循環是淚液主要的流動機制。
This research observes the morphology of epithelium of canine nasolacrimal duct by light microscope, scanning electron microscope, transmission electron microscope. On the other hand, colloidal gold particle with bovine serum albumin﹙BSA-Au﹚are used as tracer to observe the flow of the gold particle in the canine nasolacrimal system. Discuss the mechanism of absorption function, absorb tear component of epithelium in canine nasolacrimal duct.
The lacrimal drainage system arises from the lacrimal puncta , which located at the medial margin lacrimal puncta of the upper and lower eye lid. Each lacrimal puncta connects a lacrimal canaliculi, together forming a lacrimal sac （NLS）; nasolacrimal duct（NLD） leaves lacrimal sac, passes the lacrimal bone, enters the bony canal in maxillae, then the NLD deep to the nasal mucosa in the maxilla is designated as the nasal part, Under light microscopic observation, the epithelium of canine nasolacrimal duct is classified as psudostartified columnar epithelium, The epithelium of bony horizon has the thickest epithelium layer（the longest columnar epithelium）; the epithelium is carpeted with short microvilli, length between 0.2~0.5m, and occasional some long microvilli mixed it, cilia only appear around the proximal and distal of nasal cavity can be observed under SEM, especially rich around the distal portion. There are many goblet like cell, lightly- colored, exclude mucous granular on the cytoplasmic supranuclear are integrated in the dark cells, outline of the surface look like goblet cell, in the epithelium. All the epithelium contains rich mitochondria and glycogen; some of the epithelium are characterized by specific vacuoles ; some of the epithelium are characterized by specific granules that are dense, mostly homogeneous; some of the epithelium are characterized by apical tube on apical region. Occasionally , a litter amount of the mucous granular’s goblet cell in the epithelial. A wide intercellular space bounded by the interdigitating processes of the cell sides sealed beneath the luminal surface by juntional complex is an distinguished feature. Occasionally with the phagocytes appear at the epithelium intercellular space. Rich collagen fiber, different diameter of blood vessel can be observed in the subepithelial lamina propia, myelinated and unmyelinated nerve fiber gathered into bundles, mast cell, and phagocytes spread spread out in it.
We further investigate the absorption of colloidal gold particle with bovine serum albumin (BSA-Au) in the epithelium of canine nasolacrimal duct (NLD) was investigated in this study. BSA-Au suspension was injected into canine NLD through the upper or lower lacrimal canaliculi. After 40min, 80 min, 120 min, 3 hr, 4 hr, and 22 hr, the nasolacrimal epithelium in different regions of NLD, including lacrimal sac, bony vertical, bony horizontal , nasal proximal and nasal distal part, were dissected and then examined under TEM. Earliest, animals received BSA-Au injection 80 min latter; the BSA-Au particles can be observed at the luminal surface and invaginated to the vesicle on supranuclear area of NLD epithelium. At 120 min the BSA-Au particles can be observed in the vesicle and lysosome on supranuclear and perinuclear area of NLD epithelium. At 3 hr and 4 hr the BSA-Au particles can be observed in the vesicle and lysosome organelle on supranuclear and perinuclear as well as infranuclear area as well as intercellular space and lamina propia of NLD epithelium. BSA-Au has been observed in lamina propia 4hr more than 4hr. But the BSA-Au particles are not seen in any part of NLD.
Our study support the concept that the tear fluid absorbed by nasolacrimal duct into the system is the main mechanism of tear flow. |
