Isoproterenol 處理後之正常與突變肥胖鼷鼠von Ebner 氏腺的免疫組織化學與超微形態研究

Von Ebner氏腺是位於舌輪廓乳突(circumvallate papilla)下方兩側的小唾液腺(minor salivary gland)，分泌性質為純漿液性(serous)。不同味覺的感受，是經由食物分子刺激味蕾細胞上的各種接受器和離子通道的開關，經過不同的訊息傳遞造成不同的神經衝動，而使大腦產生各種味覺訊息，而von Ebner氏腺管道開口於舌輪廓乳突週遭的深溝，故勢必與味蕾接受器有密切關係。從過去的研究指出，von Ebner氏腺的功能為將製造的液體經由管道系統分泌至舌輪廓乳突漕溝內，使味覺分子溶於液體中便於與味蕾接受器結合，或是將已結合之味覺分子沖刷下來，讓味蕾接受器可以重新感應新的刺激。而正因為von Ebner氏腺與舌輪廓乳突味蕾在解剖學上的相關性，其被認為是味蕾上的附屬腺體，故形成一構造上與功能上的單位：舌輪廓乳突/von Ebner 氏腺複合體(circumvallata papilla/von Ebner gland complex, CVP/VEG complex)。db/db鼷鼠則為因缺少leptin receptor造成醣類代謝失調而患有先天性糖尿病症的突變種，糖尿病會影響病人的飲食習慣和對食物的偏好，因此吾人推論糖尿病對von Ebner氏腺也可能造成影響。故本實驗以wt/wt鼷鼠 (8~16週，20±2g) 與db/db突變之肥胖鼷鼠 (8~16週，50±2g) 作為研究對象，分成無藥物處理組與禁食後以擬交感神經藥物 (Isoproterenol) 腹腔內注射組，觀察免疫組織化學染色、半薄切片、超薄切片，比較von Ebner氏腺在形態上有何異同。主要結果如下： 1.無藥物處理組：wt/wt鼷鼠以抗α-澱粉酶之抗體去做免疫組織化學染色觀察，在腺泡細胞的細胞質中呈現深染，表示有大量表現的α-澱粉酶；而管壁細胞則較淡染，表示α-澱粉酶分泌量較少。以樹脂包埋的組織切成0.5μm之半薄切片，再以甲苯藍染色觀察，腺泡細胞分泌顆粒位於細胞頂端三分之二，均勻散布在細胞質中；管壁細胞則分泌顆粒數量很少。超微結構觀察顯示：腺泡細胞呈現錐狀，細胞核呈圓形位於底部；具發達的高基氏體；細胞底部有大量平行排列之粗糙型內質網；頂端具有分泌顆粒均勻散布在細胞質中，呈均質；靠近管腔面有微絨毛；細胞間有連結複體。導管系統主要由潤管構成，管壁細胞成立方狀；具不規則之核；粗糙型內質網較短，部分並有擴大現象，散布在細胞質中；細胞頂端有少量分泌顆粒，呈均質。腺泡及導管外圍皆有肌上皮細胞圍繞。在結締組織間或腺體實質部分，可看見神經末梢。db/db鼷鼠則跟wt/wt鼷鼠無明顯差異。 2.Isoproterenol處理組：禁食一晚後腹腔內注射20mg/kg Isoproterenol [擬交感神經興奮劑]別觀察30分鐘、1小時、2小時、4小時分泌循環期間腺泡細胞之形態變化。wt/wt鼷鼠與db/db鼷鼠在打藥後0.5到1小時期間無顯著差異，但在2小時過後，db/db鼷鼠的分泌顆粒幾乎分泌出去，留下些許空泡，到4小時才又重新製造出來；而wt/wt小鼠在2小時還可看見分泌顆粒，直到4小時分泌顆粒才逐漸減少。本研究的推論表示wt/wt鼷鼠與db/db鼷鼠在無任何藥物作用下，其von Ebner氏腺形態觀察較無顯著差異，然而再分泌循環的實驗中db/db鼷鼠的循環週期較wt/wt鼷鼠來的短。是故db/db鼷鼠與wt/wt鼷鼠von Ebner氏腺也許在形態上面無顯著改變，但在功能上也許會有些許差異性存在。

關鍵字

外分泌腺；小唾液腺；孤立束之吻端核；舌輪廓乳突；澱粉酶

並列摘要

Von Ebner’s gland (VEG) are serous glands located beneath the circumvallate papilla (CVP) of the tongue. The function of this gland is to washout the tastant molecules from taste bud for a new stimulus. Because of close anatomical relatiohship between CVP and VEG, these structures form a single functional unity designated as CVP/VEG complex. Evidences demonstrated that diabetic patients showed morphologic and physiological changes of the CVP taste buds, however, the changes of the VEG remain to be investigated. The present study aims to explore the changes of the VEG in the wt/wt and db/db mice. Adult normal wt/wt mice (C57/BL/6, 8~16 weeks, 20±2g;) and db/db mice (C57BL-Lepdb db/db, 8~16weeks, 50±2g) were used and both were divided into the control and isoproterenol-treated (20mg/kg bw, ip, at 30min,1hr, 2hr and 4hr after one day fasting) groups. Light microscopy, α-amylase immuno-histochemistry and conventional electron microscopy were applied. Our results indicate that wt/wt and db/db mice showed no apparent difference in the morphology of VEG under normal condition, and 30min and 1hr after intraperitonal injection of isoproterenol. However, 2hrs after intraperitonal injection, majority of the VEG secretory granule of db/db mice are discharged leaving vacuoles in the cytoplasm, and secretory granules did not appear even 4hrs after injection. While in wt/wt mice VEG secretory granule remain abundant 2hrs after injection, and they show only gradually decrease in number at 4hrs after injection. We conclude that the secretory cycle period of VEG in db/db mice is shorter than that of wt/wt mice.

並列關鍵字

exocrine gland ； minor salivary gland ； rostral nucleus of the solitary tract ； circumvallate papilla ； amylase

參考文獻

Azen, E.A., Hellekant, G., Sabatini, L.M., Warner, T.F., 1990. mRNAs for PRPs, statherin, and histatins in von Ebner's gland tissues. J Dent Res. 69, 1724-30.

Baum, B.J., 1993. Principles of saliva secretion. Ann N Y Acad Sci. 694, 17-23.

Bradley, R.M., Mistretta, C.M., Bates, C.A., Killackey, H.P., 1985. Transganglionic transport of HRP from the circumvallate papilla of the rat. Brain Res. 361, 154-61.

Coleman, D.L., Hummel, K.P., 1967. Studies with the mutation, diabetes, in the mouse. Diabetologia. 3, 238-48.

Coleman, D.L., Hummel, K.P., 1974. Hyperinsulinemia in pre-weaning diabetes (db) mice. Diabetologia. 10 Suppl, 607-10.

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Isoproterenol 處理後之正常與突變肥胖鼷鼠von Ebner 氏腺的免疫組織化學與超微形態研究

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