台農二號山藥及其乙酸乙酯萃取物對卵巢去除雌鼠腸道黏膜細胞形態之作用

本研究之主要目的為探討蒸熟之台農二號山藥 (Dioscorea alata L. cv. Tainung No. 2) 及其乙酸乙酯萃取物對卵巢去除雌鼠其胃腸道絨毛形態及黏膜細胞增生情況。Balb/c雌鼠8週齡大時，進行偽手術 (Sham) 或去卵巢手術 (OVX)。手術後第3天起開始餵飼實驗飼料，OVX鼠隨機分置於OVX、山藥(Yam；63%)、山藥萃取物(yam extract; 2 mg/g diet)、金雀異黃酮(Genistein 200 μg/g diet)及E2 (2 μg 17β-Estradiol /g diet)組。Sham及OVX組餵飼控制飼料，其組成主要參考AIN-93G配方，但是油改採玉米油。實驗為期十二週皆採自由飲水及攝食，小鼠犧牲前18小時注射 0.69~0.75 mg 5-bromo-2''-deoxyuridine標定試劑，之後進行斷頭犧牲，犧牲後取出的組織分別為胃底、胃主體、十二指腸、空腸、迴腸、盲腸、末端結腸以進行後續分析，測定項目為：胃腺(gastric gland)及腸道絨毛(villi)長度、寬度、面積、單側細胞核總數、單側有Labeled的細胞核數目、單側Labeled高度及肌肉層的厚度(環走與縱走平滑肌)。結果顯示OVX組的胃主體胃腺比sham組小，山藥組(yam)之胃主體胃腺長度及面積顯著比OVX組高，而山藥萃取物(yam extract)組卻沒有顯著的效果。OVX組的十二指腸絨毛面積比sham組小，yam組、yam extract組、genistein組、E2組之十二指腸絨毛面積及形態與sham組相似。肌肉層厚度的部份，OVX組的胃主體、空腸之縱走肌、環走肌厚度較sham組薄，但末端結腸肌肉層則比sham組厚。E2組之胃、十二指腸、空腸肌肉層傾向於各組中較大，而山藥組之迴腸、盲腸、末端結腸之肌肉層厚度則傾向於較其他組大。山藥萃取物(yam extract)組之效應則不明顯。 因此，本研究建議山藥可維持停經後婦女胃主體黏膜的健康，而山藥、山藥之乙酸乙酯萃取物具有保護停經後婦女十二指腸黏膜的能力。

The main purpose of this study was to investigate the effects of Dioscorea alata L. cv. Tainung No. 2 and its ethyl-acetate extract on the morphology of villi and proliferation of intestinal mucosa cells in ovariectomized female Balb/c mice.Mice were sham-operated or ovariectomized (OVX) at age of 8 weeks and were fed experimental diets after 3 days. Sham-operated mice (sham) were fed control diet (AIN-93G with corn oil) while OVX mice were randomly allocated into OVX (control diet), yam (63 g yam powder/100 g diet), yam extract (2 mg/g diet), genistein (200 mg/100 g diet), E2 (2 mg 17β-Estradiol /100 g diet) group. Animals were fed ad libitum fro 12 wk. Eighteen h before sacrifice, mice were injected with 0.69~0.75 mg 5-bromo-2''-deoxyuridine. The fundus, stomach body, duodenum, jejunum, ileum, cecum and distal colon were dissected and processed for immunohistochemical analyses. OVX reduced the sizes of gastric gland in the stomach body and villous in duodenum. Yam group reversed the OVX effect in the stomach body; while supplement with yam, yam extract, genistein or E2 completely restored the villous morphology in the duodenums to the level of sham group. OVX reduced the thickness of longitudinal and circular muscle in the stomach body, and in the jejunum, respectively, but increased the thickness of the distal colon. Estradiol diet increased the muscular thickness in stomach, duodenum and jejunum. On the other hand, yam diet tended to increase the muscular thickness in the ileum, cecum and distal colon. Yam extract did not exert significant effect in most intestinal region. These results suggest that Tainung No. 2 yam and its ethyl-acetate extracts may beneficially protect mucosa linings in the stomach and duodenum in postmenopausal women.