抗生素对新生大鼠肠道菌群和肠道免疫发育的影响

Influences of antibiotics administration on the intestinal flora and immune system development of neonatal rats

目的通过建立动物模型,探讨口服抗生素对新生大鼠肠道菌群的变化及肠道免疫发育的影响。方法选用30只7日龄新生SD大鼠,随机分为3组:抗生素组(A)、益生菌干预组(B)及对照组(C),每组10只,A组给予头孢克洛灌胃,B组先给头孢克洛灌胃,2 h后再灌长双歧杆菌,C组每天灌以等量的生理盐水,持续2周后处死大鼠,留取盲肠内容物按照张秀荣方法进行肠道菌群检测,免疫组化方法进行肠组织CD4、CD8的测定。结果A组与B、C组相比,革兰阳性杆菌占肠道总细菌数比例明显下降,革兰阴性杆菌及革兰阳性球菌占总细菌数比例明显升高,差异均有显著性(P<0.05);A组肠组织中CD4、CD8表达程度受到抑制,与B、C组相比差异有显著性(P<0.05),B、C两组所有的指标差异均无显著性。结论抗生素的应用会抑制肠道菌群的正常定植,引起菌群紊乱,进而影响肠道免疫系统发育。

Objective To investigate the impact of antibiotics administration on neenatal rat mode of intestinal flora and immunity system development. Method 30 neonate Sprague-Dewley rats （7 day olds, weighing 15 -21 g） were divided into 3 groups at random： antibiotic group （A）, probiotic intervention group （B） and control group （C）, 10 rats each group. The rats in Group A were given antibiotic （Cefaclor）. Group B were given Cefaclor first, then Bifidobacterium lungmn after 2 hours. Group C were given Sodium Chloride solution. All three groups were treated as above once per day for 2 weeks. On the fifteenth day, the rats were sacrificed. The intestinal flora in stools in Caecum of the rats were measured by ZHANG Xiu-rong method. The intestine around ileocecal junction was excised for the determination of indicators of immune system development by immunohistochemieal method. Result Compared with Group B and C, the proportion of G^＋ bacillus in the intestinal flora in group A decreased obviously, while that of G^- bacillus and G^＋ coccus in Group A increased obviously. There were a significant difference beween the groups （ P 〈 0.05）. The intestinal CD4 and CD8 expressions of Group A were inhibited, compared with Group B and C. There were a significant difference beween the groups （P 〈 0.05）. No significant difference beween Group B and C was observed. Conclusion Application of antibiotics will suppress the normal intestinal flora colonization, causing flora disturbance, thereby affecting the development of intestinal immune system.