Sacco R E, Waters W R, Rudolph K M, Drew M L
National Animal Disease Center, USDA/ARS, Ames, IA 50010, USA.
Comp Immunol Microbiol Infect Dis. 2006 Jan;29(1):1-11. doi: 10.1016/j.cimid.2005.11.001. Epub 2006 Feb 7.
Bighorn sheep are more susceptible to respiratory infection by Mannheimia haemolytica than are domestic sheep. In response to bacterial challenge, macrophages produce a number of molecules that play key roles in the inflammatory response, including highly reactive nitrogen intermediates such as nitric oxide (NO). Supernatants from monocyte-derived macrophages cultured with M. haemolytica LPS were assayed for nitric oxide activity via measurement of the NO metabolite, nitrite. In response to LPS stimulation, bighorn sheep macrophages secreted significantly higher levels of NO compared to levels for non-stimulated macrophages. In contrast, levels of NO produced by domestic sheep macrophages in response to M. haemolytica LPS did not differ from levels detected in non-stimulated cell cultures. Nitrite levels detected in supernatants of LPS-stimulated bighorn macrophage cultures treated with an inducible nitric oxide synthase (INOS) inhibitor, N(G)-monomethyl-L-arginine, were similar to that observed in non-stimulated cultures indicating a role for the iNOS pathway.
与家养绵羊相比，大角羊更容易受到溶血曼氏杆菌引起的呼吸道感染。在应对细菌挑战时，巨噬细胞会产生许多在炎症反应中起关键作用的分子，包括高活性氮中间体，如一氧化氮（NO）。通过测量NO代谢产物亚硝酸盐，检测用溶血曼氏杆菌脂多糖培养的单核细胞衍生巨噬细胞的上清液中的一氧化氮活性。响应脂多糖刺激，与未刺激的巨噬细胞相比，大角羊巨噬细胞分泌的NO水平显著更高。相比之下，家养绵羊巨噬细胞对溶血曼氏杆菌脂多糖产生的NO水平与未刺激细胞培养物中检测到的水平没有差异。在用诱导型一氧化氮合酶（INOS）抑制剂N（G）-单甲基-L-精氨酸处理的脂多糖刺激的大角羊巨噬细胞培养物的上清液中检测到的亚硝酸盐水平与在未刺激的培养物中观察到的水平相似，表明iNOS途径发挥了作用。
