Mazuski J E, Panesar N, Tolman K, Longo W E
Department of Surgery, DVA Medical Center, St. Louis, Missouri 63110, USA.
J Surg Res. 1998 Oct;79(2):170-8. doi: 10.1006/jsre.1998.5398.
Clostridium difficile infections are associated with development of the systemic inflammatory response, including the production of hepatic acute phase proteins. Lipopolysaccharide (LPS) directly stimulates the production of at least one of these proteins, a 23-kDa acute phase protein (the LPS-induced protein, or LIP) by murine hepatocytes in vitro. The aim of the present study was to determine if C. difficile toxins also stimulated the synthesis of this protein in vitro.
Cultured murine hepatocytes were treated for 24 h with various concentrations of C. difficile culture extract or purified toxins A and B in the presence or absence of dexamethasone or interleukin-1 (IL-1) receptor antagonist (IL-1 RA). The cells were then metabolically radiolabeled with [35S]methionine. Secretory proteins were identified using electrophoresis and autoradiography, and their synthesis was quantitated by image analysis of the autoradiograms.
The C. difficile culture extract, at dilutions as low as 1:200,000, significantly stimulated LIP synthesis in vitro. Toxins A and B, at concentrations as low as 1.6 and 0.02 pg/ml, respectively, also induced production of this protein. Dexamethasone further augmented C. difficile toxin-stimulated synthesis of LIP, but IL-1 RA inhibited the effects of these toxins on the synthesis of this protein. Only minimal quantities of IL-1 were found in culture supernatants following treatment with the toxins.
C. difficile toxins A and B, at very low concentrations, stimulate hepatocyte acute phase protein synthesis. Even though IL-1 RA inhibits this process, it does not appear that local production of IL-1 mediates the action of these toxins.
艰难梭菌感染与全身炎症反应的发生有关，包括肝脏急性期蛋白的产生。脂多糖（LPS）可直接刺激这些蛋白中的至少一种（一种23 kDa急性期蛋白，即LPS诱导蛋白或LIP）在体外由小鼠肝细胞产生。本研究的目的是确定艰难梭菌毒素是否也能在体外刺激该蛋白的合成。
在存在或不存在地塞米松或白细胞介素-1（IL-1）受体拮抗剂（IL-1 RA）的情况下，用不同浓度的艰难梭菌培养提取物或纯化的毒素A和B处理培养的小鼠肝细胞24小时。然后用[35S]甲硫氨酸对细胞进行代谢性放射性标记。使用电泳和放射自显影鉴定分泌蛋白，并通过对放射自显影片的图像分析对其合成进行定量。
艰难梭菌培养提取物，即使稀释至低至1:200,000，也能在体外显著刺激LIP合成。毒素A和B，分别低至1.6和0.02 pg/ml的浓度，也能诱导该蛋白的产生。地塞米松进一步增强了艰难梭菌毒素刺激的LIP合成，但IL-1 RA抑制了这些毒素对该蛋白合成的作用。在用毒素处理后的培养上清液中仅发现极少量的IL-1。
极低浓度的艰难梭菌毒素A和B可刺激肝细胞急性期蛋白合成。尽管IL-1 RA抑制了这一过程，但似乎局部产生的IL-1并不介导这些毒素的作用。
