Dawes L G, Greiner M, Joehl R J
Northwestern University, Chicago, Illinois, 60611, USA.
J Surg Res. 1999 Jan;81(1):21-6. doi: 10.1006/jsre.1998.5492.
An important function of the gallbladder is to acidify and concentrate bile. Acidification helps protect against the precipitation of calcium salts, which promote gallstone formation. Altered acidification may result in pigment gallstones. We investigated gallbladder composition in a model of TPN-associated pigment gallstones to test whether changes in acidification may be important in this gallstone model.
Ten miniswine were intravenously fed for 21 to 27 days (mean 23 days). Ten fed pig chow with intravenous infusion of saline served as controls. Gallbladder and hepatic bile electrolytes, lipids, pH, and pCO2 were measured.
All animals remained healthy and gained weight. Hepatic bile electrolytes and pH were similar among all animals. Pigs on TPN had a higher gallbladder pH and the [H+] was half the value of controls [8.1 +/- 1.6 x 10(-8) meq/liter (control) versus 3.9 +/- 0.7 x 10(-8) meq/liter (TPN)]. Gallbladder bile pCO2, sodium (Na), and potassium were higher in controls. Biliary lipids [bile salts (BS), phospholipids, and cholesterol] with TPN were decreased in both hepatic and gallbladder bile.
Unlike short-term TPN where gallbladder pH and [BS] are similar, with long-term TPN pH is higher with lower [H+], [Na], and [BS]. Despite a presumed longer residence time in the gallbladder, intravenous feeding without oral intake results in gallbladder bile that is less concentrated and acidified. Enteral stimulation may be an important stimulus for gallbladder acidification and periods without feeding may promote gallstone formation by increasing the pH of gallbladder bile.
胆囊的一项重要功能是使胆汁酸化并浓缩。酸化有助于防止促进胆结石形成的钙盐沉淀。酸化改变可能导致色素性胆结石。我们在全胃肠外营养（TPN）相关色素性胆结石模型中研究了胆囊成分，以测试酸化变化在该胆结石模型中是否重要。
十头小型猪静脉内喂养21至27天（平均23天）。十头喂食猪饲料并静脉输注生理盐水的猪作为对照。测量胆囊和肝胆汁的电解质、脂质、pH值和二氧化碳分压。
所有动物均保持健康且体重增加。所有动物的肝胆汁电解质和pH值相似。接受TPN的猪胆囊pH值较高，氢离子浓度[H⁺]是对照组的一半[8.1±1.6×10⁻⁸毫当量/升（对照组）对3.9±0.7×10⁻⁸毫当量/升（TPN组）]。对照组胆囊胆汁的二氧化碳分压、钠（Na）和钾含量较高。TPN组肝胆汁和胆囊胆汁中的胆汁脂质[胆汁盐（BS）、磷脂和胆固醇]均减少。
与短期TPN时胆囊pH值和[BS]相似不同，长期TPN时pH值较高，而[H⁺]、[Na]和[BS]较低。尽管推测在胆囊中的停留时间较长，但无口服摄入的静脉内喂养导致胆囊胆汁浓缩程度和酸化程度较低。肠内刺激可能是胆囊酸化的重要刺激因素，禁食期可能通过提高胆囊胆汁的pH值促进胆结石形成。
