Keelan M, Cheeseman C, Walker K, Thomson A B
Radiat Res. 1986 Jan;105(1):84-96.
Previous studies have shown that external abdominal irradiation is associated with alterations in intestinal morphology and function. The activity of the jejunal brush border membrane (BBM) enzyme markers sucrase (S) and alkaline phosphate (AP) were not altered by 600 rad irradiation in the rat. In contrast, ileal BBM, AP, and AP/S were increased 3, 7/8, and 28 days postirradiation. The total lipid composition of the jejunal BBM was lower than in control animals only at 3 days postirradiation; this was due to a decrease in the total free fatty acid content. In addition to a lower total free fatty acid content, the ileal BBM contained an increased amount of total phospholipid (PL) which resulted in an increased phospholipid/cholesterol ratio at 3 days following irradiation. Variations in the BBM phospholipid composition occurred in both jejunum and ileum. In the jejunal BBM, the phospholipid composition changes did not alter the choline or amine phospholipid content; therefore, the choline/amine phospholipid ratio was unaffected by irradiation at 600 rad. In the ileal BBM, the phosphatidyl ethanolamine was increased at 3, 7/8, 14, and 28 days following irradiation. The choline/amine phospholipid ratio was not altered in the ileal BBM due to concomitant increases in lecithin content. Jejunal villus height, villus surface area, and the number of cells per villus were decreased at 3 days postirradiation, but increased by day 7/8 and 14 postirradiation to levels much higher than observed in control jejunal villi. The mucosal surface area was decreased at 3 and 7/8 days following irradiation but returned to control values by Day 14. Jejunal microvillus morphology was unaffected by irradiation. Few significant changes were observed in ileal villus morphology following irradiation at 600 rad. Ileal villus height, villus surface area, and mucosal surface area did not change, but the number of cells per villus initially decreased at 3 days and then increased beyond control values at 7/8 and 14 days postirradiation. Ileal microvillus height was significantly decreased only at 7 days postirradiation, while the number of microvilli per micron was increased only at 3 days postirradiation. This study suggests that changes in intestinal morphology and brush border composition may contribute to the altered passive permeation toward lipids which has been reported following abdominal radiation.
先前的研究表明，腹部外照射与肠道形态和功能的改变有关。大鼠接受600拉德照射后，空肠刷状缘膜（BBM）酶标志物蔗糖酶（S）和碱性磷酸酶（AP）的活性未发生改变。相比之下，照射后3天、7/8天和28天，回肠BBM、AP以及AP/S升高。空肠BBM的总脂质成分仅在照射后3天低于对照动物；这是由于总游离脂肪酸含量降低所致。除了总游离脂肪酸含量较低外，回肠BBM的总磷脂（PL）含量增加，导致照射后3天磷脂/胆固醇比值升高。空肠和回肠的BBM磷脂成分均发生了变化。在空肠BBM中，磷脂成分的变化未改变胆碱或胺磷脂含量；因此，600拉德照射未影响胆碱/胺磷脂比值。在回肠BBM中，照射后3天、7/8天、14天和28天磷脂酰乙醇胺增加。由于卵磷脂含量同时增加，回肠BBM中的胆碱/胺磷脂比值未发生改变。照射后3天空肠绒毛高度、绒毛表面积和每个绒毛的细胞数量减少，但在照射后7/8天和14天增加至远高于对照空肠绒毛的水平。照射后3天和7/8天黏膜表面积减少，但在第14天恢复至对照值。空肠微绒毛形态未受照射影响。600拉德照射后，回肠绒毛形态几乎没有显著变化。回肠绒毛高度、绒毛表面积和黏膜表面积未改变，但每个绒毛的细胞数量最初在照射后3天减少，然后在照射后7/8天和14天增加至超过对照值。回肠微绒毛高度仅在照射后7天显著降低，而每微米微绒毛数量仅在照射后3天增加。本研究表明，肠道形态和刷状缘成分的变化可能导致腹部放疗后报道的脂质被动渗透改变。
