Margenthaler Julie A, Landeros Keith, Kataoka Masaaki, Eilers Mark, Ku Grace, Flye M Wayne
Department of Surgery, Washington University School of Medicine, St. Louis, Missouri, USA.
J Surg Res. 2003 Jun 1;112(1):102-10. doi: 10.1016/s0022-4804(03)00133-1.
Prior administration of the Gram-positive bacteria Propionibacterium acnes (PA) results in hypersensitivity and hepatocyte necrosis to a subsequent low dose of lipopolysaccharide (LPS). Endotoxin tolerance has been shown to prevent lethality after ischemia/reperfusion injuries, sepsis, and endotoxic shock. We investigated whether prior induction of LPS tolerance could prevent subsequent PA-priming and LPS-induced death. The levels of known effector cytokines possibly responsible for these changes were measured.
C57BL/6 (B6) mice were given heat-killed PA (0.5 mg/mouse) followed 7 days later by LPS (20 microg/mouse). In parallel experiments, B6 mice were pretreated with a single 20 microg/mouse dose of LPS (lethal dose = 800 microg/mouse) 7 days prior to PA priming. Animal survival, liver and spleen weights, and histology were examined. Cytokine levels of the inflammatory cytokines interferon-alpha, tumor necrosis factor-gamma, interleukin (IL)-6, and IL-12 and the anti-inflammatory cytokines IL-4 and IL-10 were measured by enzyme-linked immunosorbent assay and by reverse-transcription polymerase chain reaction.
Hepatomegaly, splenomegaly, and hepatocyte necrosis with death developed in all PA-primed B6 mice challenged with LPS. However, 83% of B6 mice given a tolerizing dose of LPS prior to PA survived (P < 0.01) without any increase in liver or spleen weights and without histological evidence of necrosis. Markedly decreased in vivo and in vitro inflammatory (interferon-alpha, tumor necrosis factor-gamma, IL-6, and IL-12) cytokine levels corresponded with survival in the LPS-tolerant mice. Endotoxin tolerance and subsequent survival were also associated with an increase in anti-inflammatory (IL-4 and IL-10) mRNA expression.
Lethal PA-primed LPS-induced hepatic injury can be prevented by administering a tolerizing dose of LPS prior to PA-priming. LPS protects the liver by preventing hepatic mononuclear cellular infiltration, reducing the production of the toxic proinflammatory cytokines, and inducing the production of endogenous anti-inflammatory cytokines.
预先给予革兰氏阳性菌痤疮丙酸杆菌（PA）会导致对随后低剂量脂多糖（LPS）产生超敏反应和肝细胞坏死。内毒素耐受已被证明可预防缺血/再灌注损伤、脓毒症和内毒素休克后的致死情况。我们研究了预先诱导LPS耐受是否能预防随后PA激发和LPS诱导的死亡。检测了可能导致这些变化的已知效应细胞因子的水平。
给C57BL/6（B6）小鼠注射热灭活的PA（0.5毫克/只小鼠），7天后再注射LPS（20微克/只小鼠）。在平行实验中，B6小鼠在PA激发前7天用单次剂量20微克/只小鼠的LPS（致死剂量 = 800微克/只小鼠）进行预处理。检查动物存活率、肝脏和脾脏重量以及组织学情况。通过酶联免疫吸附测定和逆转录聚合酶链反应测量炎性细胞因子干扰素-α、肿瘤坏死因子-γ、白细胞介素（IL）-6和IL-12以及抗炎细胞因子IL-4和IL-10的细胞因子水平。
所有用LPS攻击的PA激发B6小鼠均出现肝肿大、脾肿大以及伴有死亡的肝细胞坏死。然而，83%在PA之前给予耐受剂量LPS的B6小鼠存活（P < 0.01），肝脏或脾脏重量没有增加，且没有坏死的组织学证据。LPS耐受小鼠体内和体外炎性（干扰素-α、肿瘤坏死因子-γ, IL-6和IL-12）细胞因子水平显著降低与存活情况相符。内毒素耐受和随后的存活还与抗炎（IL-4和IL-10）mRNA表达增加有关。
通过在PA激发前给予耐受剂量的LPS可预防致死性PA激发的LPS诱导的肝损伤。LPS通过防止肝脏单核细胞浸润、减少有毒促炎细胞因子的产生以及诱导内源性抗炎细胞因子的产生来保护肝脏。
