Singh J, Murray R D, Mshelia G, Woldehiwet Z
Department of Veterinary Clinical Science, University of Liverpool Teaching Hospital, Leahurst, Neston, Wirral, UK.
Vet J. 2008 Mar;175(3):301-9. doi: 10.1016/j.tvjl.2007.02.003. Epub 2007 Apr 2.
The post-partum period in cattle is characterised by an increased risk of infection of the uterus, as the anatomical barriers are broached during parturition and remain open for several days. Infection of the uterus is largely influenced by the balance between bacterial contamination and the local and systemic immune status during pregnancy and around parturition. Infectious diseases are more prevalent during this period, because of an impaired immune status before and immediately after parturition. Neutrophils play a primary role in the defence of the uterus against infection. Influx of neutrophils into the uterus is thought to be mediated by chemoattractants, chemokines and adhesion molecules, such as beta2-integrin (complement receptor 3) and L-selectin (CD62L). Other cellular components activated in the uterus during this period include lymphocytes, eosinophils, mast cells and macrophages. The major classes of immunoglobulins (IgM, IgA and IgG), either by passive diffusion or local production, play an important protective role in the uterus by acting as opsonins to enhance phagocytosis, stimulating the complement pathways or blocking pathogens from adhering to mucosal surfaces. Endometrial cells express toll-like receptor 4 (TLR4), which recognises lipopolysaccharides of Escherichia coli and other Gram negative bacteria, the most common causes of bovine endometritis. Activation of TLR4 triggers the production of tumour necrosis factor alpha and other pro-inflammatory cytokines. The periparturient period is also characterised by an increased secretion of prostaglandin F(2alpha), which enhances uterine immune defences.
牛的产后时期的特点是子宫感染风险增加，因为在分娩过程中解剖屏障被突破且会持续开放数天。子宫感染在很大程度上受孕期及分娩前后细菌污染与局部和全身免疫状态之间平衡的影响。由于分娩前和分娩后立即出现免疫状态受损，传染病在此期间更为普遍。中性粒细胞在子宫抵御感染中起主要作用。中性粒细胞流入子宫被认为是由趋化因子、趋化因子和黏附分子介导的，如β2整合素（补体受体3）和L选择素（CD62L）。在此期间子宫内激活的其他细胞成分包括淋巴细胞、嗜酸性粒细胞、肥大细胞和巨噬细胞。主要类别的免疫球蛋白（IgM、IgA和IgG），通过被动扩散或局部产生，在子宫中起重要的保护作用，它们作为调理素增强吞噬作用、刺激补体途径或阻止病原体黏附于黏膜表面。子宫内膜细胞表达Toll样受体4（TLR4），其识别大肠杆菌和其他革兰氏阴性菌的脂多糖，这些细菌是牛子宫内膜炎最常见的病因。TLR4的激活触发肿瘤坏死因子α和其他促炎细胞因子的产生。围产期的另一个特点是前列腺素F（2α）分泌增加，这增强了子宫的免疫防御。
