Estrada C, Gómez C, Martín C
Department of Physiology, Faculty of Medicine, Universidad Autónoma de Madrid, Spain.
J Cereb Blood Flow Metab. 1995 Nov;15(6):920-8. doi: 10.1038/jcbfm.1995.117.
The effects of tumor necrosis factor-alpha (TNF-alpha) on the production of the vasoactive substances nitric oxide (NO) and endothelin-1 (ET-1) were investigated in cerebrovascular cells in culture. Bovine cerebral endothelial cells (BCEC) stained positively for NADPH-diaphorase/NO synthase activity and spontaneously produced nitrite, a stable NO oxidation product, which accumulated in the culture medium in a linear way for 48 h. Low concentrations of TNF-alpha (0.5-2 ng/ml) significantly enhanced nitrite production after a 24-h incubation. Higher concentrations or longer exposure times resulted in a cytotoxic effect that altered cell morphology, released lactate dehydrogenase (LDH) to the culture medium, and reduced the protein content. Dexamethasone, but not the NO synthase inhibitor N-iminoethyl-L-ornithine (L-NIO), prevented the cytotoxic effect of TNF-alpha in BCEC. TNF-alpha also significantly enhanced nitrite production in bovine cerebral smooth muscle cells (BCSMC). The enhancement was detected at all times between 8 and 72 h and at all concentrations tested (2-100 ng/ml). Signs of cytotoxicity were not observed in BCSMC after incubation with TNF-alpha. ET-1 was constitutively secreted by BCEC. The production of ET-1 was stimulated by thrombin. TNF-alpha enhanced the release of ET-1 in BCEC, and this enhancement was not modified by the simultaneous addition of interferon-gamma (IFN-gamma). BCSMC did not produce ET-1, either spontaneously or in the presence of TNF-alpha, IFN-gamma, or of both together.(ABSTRACT TRUNCATED AT 250 WORDS)
在体外培养的脑血管细胞中，研究了肿瘤坏死因子-α（TNF-α）对血管活性物质一氧化氮（NO）和内皮素-1（ET-1）生成的影响。牛脑内皮细胞（BCEC）经烟酰胺腺嘌呤二核苷酸磷酸黄递酶/NO合酶活性染色呈阳性，并自发产生亚硝酸盐（一种稳定的NO氧化产物），其在培养基中呈线性累积达48小时。低浓度的TNF-α（0.5 - 2 ng/ml）孵育24小时后可显著增强亚硝酸盐的生成。更高浓度或更长暴露时间会产生细胞毒性作用，改变细胞形态，使乳酸脱氢酶（LDH）释放到培养基中，并降低蛋白质含量。地塞米松可预防TNF-α对BCEC的细胞毒性作用，而NO合酶抑制剂N-亚氨基乙基-L-鸟氨酸（L-NIO）则不能。TNF-α也显著增强了牛脑平滑肌细胞（BCSMC）中亚硝酸盐的生成。在8至72小时的所有时间点以及所有测试浓度（2 - 100 ng/ml）下均检测到这种增强作用。TNF-α孵育BCSMC后未观察到细胞毒性迹象。ET-1由BCEC组成性分泌。凝血酶可刺激ET-1的生成。TNF-α增强了BCEC中ET-1的释放，且同时添加干扰素-γ（IFN-γ）不会改变这种增强作用。BCSMC无论是自发还是在TNF-α、IFN-γ单独或两者共同存在的情况下均不产生ET-1。（摘要截短于250字）
