Stratton M D, Chandel B, Deshpande Y, Kaminski D L, Li A P, Vernava A M, Longo W E
Department of Surgery, St. Louis University Medical Center, MO 63110-0250.
Prostaglandins. 1994 Dec;48(6):367-75. doi: 10.1016/0090-6980(94)90003-5.
Antibiotic-associated colitis is caused by Clostridium difficile toxin. However, the pathophysiology of this entity is poorly understood. The aim of this study was to determine the effects of C. difficile toxin on colonocyte cyclooxygenase and phospholipase A2 (PLA2) activity. A transformed colonocyte cell line (Caco-2) was grown to confluency on 6 well plates. The cells were stimulated with graded concentrations of C. difficile toxin. In separate experiments, the cells were pretreated for one hour prior to stimulation with the cyclooxygenase inhibitor, indomethacin, or the glucocorticoid, dexamethasone. The culture media was collected one hour following C. difficile stimulation. Prostaglandin E2 (PGE2), 6-keto prostaglandin F1 alpha (6KPGF), thromboxane B2 (TxB2) and leukotriene B4 (LTB4) levels were determined in the media by an ELISA. Platelet activating factor (PAF) concentration was determined by a RIA. C. difficile toxin stimulated PGE2 and 6KPGF levels in a dose dependent fashion but failed to stimulate TxB2, LTB4 or PAF. Prostanoid production was inhibited by indomethacin dose dependently but was not inhibited by dexamethasone. The presence of indomethacin resulted in production of PAF. Our results show that the effects of C. difficile toxin on colonocytes are mediated by cyclooxygenase activity. The increase in PAF formation associated with indomethacin administration suggests that the prostanoids modulate PLA2 activity and inhibit PAF formation.
抗生素相关性结肠炎由艰难梭菌毒素引起。然而，该疾病实体的病理生理学仍知之甚少。本研究的目的是确定艰难梭菌毒素对结肠细胞环氧化酶和磷脂酶A2（PLA2）活性的影响。将转化的结肠细胞系（Caco-2）接种于6孔板，培养至汇合状态。用不同浓度的艰难梭菌毒素刺激细胞。在单独的实验中，细胞在接受艰难梭菌毒素刺激前1小时，先用环氧化酶抑制剂吲哚美辛或糖皮质激素地塞米松预处理。在艰难梭菌刺激1小时后收集培养基。通过酶联免疫吸附测定法（ELISA）测定培养基中前列腺素E2（PGE2）、6-酮前列腺素F1α（6KPGF）、血栓素B2（TxB2）和白三烯B4（LTB4）的水平。通过放射免疫分析法（RIA）测定血小板活化因子（PAF）浓度。艰难梭菌毒素以剂量依赖的方式刺激PGE2和6KPGF水平，但未能刺激TxB2、LTB4或PAF。前列腺素的产生被吲哚美辛剂量依赖性抑制，但未被地塞米松抑制。吲哚美辛的存在导致PAF的产生。我们的结果表明，艰难梭菌毒素对结肠细胞的作用是由环氧化酶活性介导的。与吲哚美辛给药相关的PAF形成增加表明，前列腺素调节PLA2活性并抑制PAF形成。
