Shaheen A A, Hassan S H
Department of Biochemistry, Faculty of Pharmacy, Cairo University, Egypt.
Strahlenther Onkol. 1994 Aug;170(8):467-70.
The aim of this investigation was to determine whether pre- or post-administration of vitamin A will be effective in reducing the radiation-induced alterations in intestinal disaccharidases in rats.
Rats were subjected to fractionated whole-body irradiation (20 x 0.5 Gy). Intestinal lactase activity as well as maltase and sucrase activities were assessed. Vitamin A was administered at daily intraperitoneal dose of 15,000 IU/kg body weight for 7 days prior to radiotherapy and thereafter twice weekly throughout therapy up to 7 days post irradiation.
In irradiated rats a marked decrease in intestinal lactase activity to about one-fourth of those in non-irradiated rats was observed. In addition, a significant reduction in maltase and sucrase activities to one half of the control group was observed. The application of vitamin A significantly improved the radiation-induced inhibition of intestinal enzymes. Pretreatment application of vitamin A is more efficient to protect against radiation injury than a posttreatment application.
The usage of vitamin A for modulation of radiation-induced changes in intestinal enzymes provides sufficient protection against treatment side effects induced by large volume radiotherapy.
本研究旨在确定维生素A在放疗前或放疗后给药是否能有效减轻大鼠肠道双糖酶的辐射诱导变化。
大鼠接受分次全身照射（20×0.5 Gy）。评估肠道乳糖酶活性以及麦芽糖酶和蔗糖酶活性。在放疗前7天，每天以15,000 IU/kg体重的腹腔注射剂量给予维生素A，此后在整个治疗过程中每周两次，直至放疗后7天。
在受照射大鼠中，观察到肠道乳糖酶活性显著降低至未受照射大鼠的约四分之一。此外，麦芽糖酶和蔗糖酶活性显著降低至对照组的一半。维生素A的应用显著改善了辐射诱导的肠道酶抑制。维生素A预处理比后处理更有效地预防辐射损伤。
使用维生素A调节辐射诱导的肠道酶变化可充分预防大剂量放疗引起的治疗副作用。
