干酪乳杆菌细胞壁成分诱导小鼠冠状动脉炎的实验研究

Experimental Study on Coronary Arteritis Induced by Immunization of Mice with Lactobacillus Casei Cell Wall Extract

目的 探讨干酪乳杆菌细胞壁成分（LCWE）诱导产生川崎病（KD）冠状动脉炎动物模型的可能性。方法 制备LCWE（1g／L）。将100只BALB／C小鼠随机分为实验组和对照组各50只。分别腹腔注射05mL LCWE和PBS。注射后1、3、5、10和28d每组取10只小鼠分批采血，处死，留取心脏病理标本，并测量体质量、心脏、脾脏重量、脾脏／体质垃及心脏／体质量比值。结果 1．冠状动脉炎损害的发生率：实验组小鼠为92．5％，对照组为4．0％（P〈0．001）。2．病理学改变：心脏标本HE染色光镜检查显示冠状动脉炎损害早期（1-3d）以中性粒细胞为主伴少量淋巴细胞和单核细胞浸润，血管中膜平滑肌细胞消失，晚期（28d）以巨噬细胞为主伴少量中性粒细胞、淋巴细胞浸润，冠脉管壁纤维细胞增生纤维化以及心内膜、心外膜、心肌炎，升主动脉及小血管周围炎。电镜检查显示实验组急性期冠状动脉血管内皮细胞大量广泛空泡变性，坏死、脱落，基底膜疏松，严重线粒体肿胀，内质网扩大，中膜增厚，中层细胞消失，纤维蛋白样沉积等改变。对照组各阶段心脏和血管均无炎症。3．免疫学指标：外周血T细胞亚群检测显示实验组小鼠CD4^＋与CD8^＋T细胞亚群的绝对数量明显增高（P〈0．05），均在3d达到高峰，为（8．23±1．32）及（6．19±1．08）×10^9／L。模型小鼠注射LCWE后3d血浆TNF-α、IL-1β及IL-6水平较对照组明显增高，有显著性差异。4．实验组小鼠在d5、10时体质量、心脏、脾脏重量及脾脏／体质量、心脏／体质量比值均较对照组降低，差异有极显著性（P均〈0．05）。结论 LCWE单次腹腔注射能够诱导BALB／C小鼠产生冠状动脉炎及心肌炎病理改变，是一种能够可靠反映KD冠状动脉炎的良好动物模型。其群体发病率高，病理损害与LCWE诱导的免疫反应有关。

Objective To establish an animal model of coronary arteritis induced by lactobacillus casei cell wall extract （LCWE） in mice with mirrors Kawasaki disease. Methods LCWE was preparated and diluted to 1 g/L. Then it was used for immunization of geneti- cally predisposed mice to establish animal model of coronary arteritis. There were 50 mice as experimental group and 50 mice as control group. Mice （4 weeks old） were respectively injected with 500μL of PBS containing 0.5 nag LCWE or PBS alone on day 0, and 10 mice in each group were sacrificed on days 1,3, 5,10 and 28. Blood was collected and cardiac tissues were removed and embedded in the embedding medium OCT. Body weight （BW）, spleen weight （SpW） and heart weight （HW） were compared between experimental group and control group. Results 1. After the injection with LCWE , the ratio which BALB/C mice developed histological coronary arteritis of experimental group was about 92.5 % and that of control group was 4.0 % （ P〈0.001 ）. 2. Pathological features of being characteristic of many neutrophil and a few mononuclear cell infiltrations, severe medial lesions with smooth muscle cell loss and inflammatory cell infiltration, and adventitial lesions with invasion of some inflammatory cells in the ostium of coronary arteries and main coronary artery at 1-3 days. After LCWE treatment lesions were found at the ostium of the coronary artery showing mild intirnal thickening with prominant macrophage and slight neutrophil infiltration at 4 weeks. EM microscopy showed different degrees of swelling, necrosis and abscission of endothelial cells, aggregation of chromatain, degeneration of smooth muscle cell, swelling of mitochondria and augmentation of endoplasmic reticulum in the coronary artery of experimental group. 3. Experimental group significantly improved the absolute number of CD4^＋ and CD8^＋ T cells （ P 〈 0.05 ）. The absolute number of CD4^＋ and CD8^＋ T cells reached the peak of （8.23 ±1.32）×10^9/L and （6.19±1.08）×10^9/L at 72 hours. In LCWE groups, levels of TNF -α, IL-1β, IL - 6 in blood were significantly improved at 3^rd day, compared with those of control group （ all P〈0.05 ）. BW, SpW and HW were lightened at 3^rd and 5^th day in the LCWE group compared with thcse of control group. There was significant difference between them（all P 〈 0.05 ）. Conclusions Coronary arteritis and myocarditis can been induced by immunization of mice with LCWE injected single, pathological changes were typical , the morbidity meets the requirement of research. LCWE- induced coronary arteritis in mice mirrors Kawasaki disease.