腸道細(xì)菌及其毒素的移位可能是自身免疫性疾病發(fā)病的重要因素。這種猜測在一段時間內(nèi)被認(rèn)為是正確的。但是由于沒有合適的研究工具，因此沒有得到廣泛研究。事實上，研究表明壓力、手術(shù)和輕微胃腸道疾病等顯著增加了黏膜通透性。因此，這種情況下顯著增加了細(xì)菌從腸黏膜進(jìn)入人體的機(jī)率。

Chondrex公司提供FITC標(biāo)記的右旋糖苷及D-木糖檢測試劑盒用于評估體內(nèi)和體外大分子對半透膜的通透性。

通透性評估試劑盒

通透性評估試劑-熒光標(biāo)記的右旋糖苷

一般來說，分子通過腸道進(jìn)入身體發(fā)生在細(xì)胞間或通過細(xì)胞進(jìn)入體內(nèi)。熒光標(biāo)記的右旋糖苷提供了簡單，可靠的方法用于評估體外或體內(nèi)細(xì)胞旁通透性。另一種方法是，通過D-木糖測定跨細(xì)胞通透性，也就是說通過D-木糖作為被動載體介導(dǎo)小腸吸收。

FITC-標(biāo)記的右旋糖苷

一些研究表明壓力、手術(shù)和輕微胃腸道疾病等顯著增加了黏膜通透性。熒光標(biāo)記的右旋糖苷提供了簡單，可靠的方法用于評估半透膜功能。關(guān)于FITC-標(biāo)記的右旋糖苷的分子量，（ 40kDa）,有研究表明在大腸桿菌中大多數(shù)蛋白分子量為25-120kDa,這表明具有生物學(xué)意義的蛋白質(zhì)在該范圍內(nèi)。因此Chondrex提供40kDa FITC-右旋糖苷作為相關(guān)大分子標(biāo)記物，用于體外或體內(nèi)半透膜通透性研究。

檢測流程：

1）飼喂前和實驗過程中，禁食4小時。

2）口服40 kDa FITC-Dextran (10 mg/250 µl/mouse)。

3）3小時后，收集血漿。

4）1:2 (或更大)用PBS稀釋血漿

5）取50-100ul上去到96孔板。讀取熒光值：Ex: 490 nm  Em: 530 nm

     用PBS稀釋的FITC- 右旋糖苷繪制的標(biāo)準(zhǔn)曲線

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