双歧杆菌对新生鼠坏死性小肠结肠炎模型肠损伤保护机制的研究

发布时间：2019-05-19 07:20

【摘要】： 目的探讨补充双歧杆菌的保护作用是否与降低肠组织PAF和提高肠组织SIgA有关,为应用双歧杆菌防治新生儿坏死性小肠结肠炎提供科学依据。 方法选用84只两日龄新生SD大鼠,雌雄不限,随机分三组:实验组(A)、对照组(B)、空白对照组(C),每组n=28。A组:每只0.04g(含2亿个活菌)双歧杆菌灌胃(用PH7.4的生理盐水配制0.2ml/只),持续一周,每天一次;B和C组:每只0.2ml生理盐水灌胃持续一周,每天一次。实验组和对照组一周后,均注射LPS(5mg/kg,用生理盐水配成5mg/ml)建立坏死性小肠结肠炎模型。三组于A组和B组腹腔注射LPS后,2、6、12、24小时,每个时间点随机抽取7只采用断颈法处死,解剖留取十二指肠下端至直肠上端肠道组织,其中回盲部近端肠管观察SD鼠病理标本,剩余的肠管ELISA检测肠组织匀浆中PAF、SIgA含量。采用SPSS16.0统计软件,计量资料结果以均值±标准差(ˉX±SD)表示,组间比较采用t检验法,P0.05提示差异有显著统计学意义。 结果 1.各实验组新生SD大鼠肠组织病理形态学改变 新生SD大鼠注射LPS后,B组中新生SD大鼠出现懒动、萎靡,1-2小时出现腹胀、腹泻,6-12小时上述症状加重,同时出现腹式呼吸增快,口唇青紫,少动,体毛凌乱、少光泽,严重者抽搐,四肢青紫,周身凉,甚至死亡;动物处死后,见胃储留明显,肠壁及肠系膜充血,肠管扩张、水肿,肠腔渗出物增多,严重者见肠壁点、片状出血坏死,24小时存活者上述症状缓解。H-E染色后光镜下变化:新生SD大鼠注射LPS后,B组2小时肠上皮细胞变性,绒毛萎缩;6小时可见小肠上皮结构完全消失,绒毛腺体脱落、缺失,固有层毛细血管充血,炎细胞浸润;12小时部分肠绒毛上皮细胞开始修复,但绒毛结构不清;24小时后肠绒毛结构明显。A组较B组相比,症状较轻。 2.各组新生SD大鼠肠组织PAF、SIgA含量变化 B组肠组织PAF的含量在2h、6h、12h与C组比较有显著增加(P0.05),A组肠组织PAF的含量在2h、6h、12h与B组比较有显著减少(P0.05)。A组肠组织SIgA的含量在2h、6h、12h与C组比较有显著增加(P0.05),B组肠组织SIgA的含量在2h、6h、12h与A组比较有显著减少(P0.05)。 结论 1.内毒素引起新生鼠坏死小肠结肠炎模型中,外源性给予双歧杆菌实验组肠组织PAF的含量与对照组比较明显降低,表明双歧杆菌可能通过抑制炎症级联反应中PAF表达而保护肠道,能减轻新生鼠坏死性小肠结肠炎模型肠组织病理改变。 2.内毒素引起新生鼠坏死小肠结肠炎模型中,外源性给予双歧杆菌实验组肠组织SIgA的含量与对照组比较明显增加,表明双歧杆菌可能通过提高肠道免疫SIgA表达而保护肠道。
[Abstract]:Objective to investigate whether the protective effect of Bifidobacillus supplementation is related to the decrease of PAF in intestinal tissue and the increase of SIgA in intestinal tissue, and to provide scientific basis for the application of Bifidobacterium in the prevention and treatment of neonatal necrotizing enterocolitis. Methods 84 two-day-old neonatal SD rats, male and female, were randomly divided into three groups: experimental group (A), control group (B), blank control group (C), Group A: 0.04g Bifidobacterium (0.2ml/ only prepared with PH7.4 saline) was given intragastrically for one week, once a day. Group B and C: each 0.2ml saline was given intragastrically once a day. One week later, the experimental group and the control group were injected with LPS (5 mg 路kg ~ (- 1) and normal saline (5mg/ml) to establish the model of necrotizing enterocolitis. After intraabdominal injection of LPS in group A and group B, 2, 6, 12, 24 hours, 7 rats in each time point were randomly selected and killed by neck amputation, and the intestinal tissues from the lower end of the duodenum to the upper end of the rectum were dissected. The pathological specimens of SD mice were observed by proximal ileocecum, and the content of PAF,SIgA in intestinal homogenate was detected by residual intestinal ELISA. Using SPSS16.0 statistical software, the results of measurement data were expressed by mean 卤standard deviation (鈮，

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