摘要
目的探讨添加双歧杆菌对新生鼠坏死性小肠结肠炎(necrotizing enterocolitis,NEC)模型肠损伤的保护作用。方法 32只新生SD大鼠按析因设计随机分成4组,每组动物8只。A1B1组为NEC模型组并添加双歧杆菌(109CFU/d),A1B2组为NEC模型组,但未添加双歧杆菌;A2B1组为对照组并添加双歧杆菌(109CFU/d),A2B2组为对照组,且未添加双歧杆菌。在出生48 h开始给予鼠配方奶人工喂养,100%氮气缺氧90 s,4℃冷刺激10 min,每天2次,连续3 d,建立新生大鼠NEC模型;在最后1次缺氧、冷刺激后24 h空腹断头处死小鼠,解剖留取十二指肠下端至直肠上端肠道组织,其中,回盲部近端肠管进行病理学检查及肠损伤评分,组织学评分≥2为NEC,其余肠管进行肠细胞凋亡率检测及电镜观察。采用流式细胞仪检测肠细胞凋亡率。SPSS 11.0统计学软件进行统计分析,α=0.05为显著性检验标准。结果造模后,A1B1组、A1B2组相继出现腹泻、腹胀、生长发育减慢和活动度减少,显微镜下可见肠黏膜坏死、黏膜下层出血以及肌肉层坏死等肠损伤表现,透射电镜显示肠黏膜出现大量凋亡细胞,形成凋亡小体,但A1B1组程度较轻。A1B1、A1B2、A2B1和A2B24组肠损伤组织病理评分(x±s)分别为2.04±0.52、3.38±0.55、0.33±0.36和0.38±0.33,肠细胞凋亡率分别为(23.97±10.48)%、(47.28±21.98)%、(11.42±4.75)%和(12.16±4.95)%;各组间肠损伤组织评分、肠细胞凋亡率差异有显著统计学意义(H分别为26.657、20.916,P均<0.01);与A1B2组相比,A1B1组新生鼠肠损伤组织评分、肠细胞凋亡率均明显降低,但仍高于A2B1、A2B22个对照组(P均<0.01);肠组织损伤评分值、肠细胞凋亡率均受到NEC造模和添加双歧杆菌两个因素的影响,NEC造模与补充双歧杆菌之间均存在交互作用。结论添加双歧杆菌可以降低新生鼠NEC肠损伤程度,可能通过抑制肠上皮细胞凋亡,从而降低新生大鼠发生NEC危险性。
Objective To explore the protective effects and mechanism of Bificobacterium longum in inhibiting intestinal injury of neonatal Sprague-Dewley rat necrotizing enterocolitis（NEC） model.Method According to 2×2 factor analysis,32 neonate Sprague-Dewley rats（48 hours old,weighing 5～10 g） were divided into 4 groups（A1B1,A1B2,A2B1 and A2B2,n=8）.Rats in Group A1B1 and A1B2 were made into NEC models by being separated from mother rats and fed with rat milk substitute,then exposed to 100% N2 for 90 second and 4 ℃ temperature for 10 minutes,twice a day during 3 consecutive days.Rats in group A1B1 was given Bifidobacterium longum（108CFU/day） while those in group A1B2 was not.Rats in groups A2B1 and A2B2 served as control groups,and the rats in group A2B1 was given Bifidobacterium longum（108CFU/day） while those in group A2B2 was not.On the 4th day the rats were sacrificed and intestinal tissue were collected.The apoptosis ratio of intestinal cells were determined with flow cytometry（FCM） and the morphological changes in intestinal musca were observed under light and electron microscope.The intestine around ileocecal junction of all the subjects were scored in double-blind way,and the mean score more than 2 were considered NEC.Kruskal-Wallis H test and factorial ANOVA were used to analyze difference among each groups.α=0.05 was considered significant.Result The rats in groups A1B1 and A1B2 had diarrhea,abdominal distention,growth and development stepping down,activity reducing,and the apoptosis cells and apoptic body in intestine mucosa were observed.Compared with group A1B2,there was remarkable relief after being given Bificobacterium longum in group A1B1.The scores of histological evaluation（x-±s） in groups A1B1,A1B2,A2B1 and A2B2 were 2.04±0.52,3.38±0.55,0.33±0.36 and 0.38±0.33 respectively,and the apoptosis ratio of intestinal cells were（23.97±10.48）%,（47.28±21.98）%,（11.42±4.75）% and（12.16±4.95）%,respectively.The score of histopatholigical and the apoptosis ratio of intestinal cells had significant difference among groups.Comparing with that of group A1B2,the score of histopatholigical and the apoptosis ratio of intestinal cells of group A1B1 reduced,but that of group A1B1 was higher than the two control groups significantly.By factorial ANOVA,two factors of modeling and Bificobacterium longum intervention had taken effect on the score of histopatholigical,the apoptosis ratio of intestinal cells.There were interaction between modeling and Bificobacterium longum intervention.Conclusion Bificobacterium longum is beneficial to reduce the intestinal injury of neonate rats caused by NEC and decrease the incidence of NEC.It may reduce the apoptosis ratio of intestinal cells,which will be underlying protective mechanisms of Bificobacterium longum on NEC.
出处
《中国微生态学杂志》
CAS
CSCD
2010年第8期682-685,689,共5页
Chinese Journal of Microecology
基金
福建省卫生厅青年科研课题资助(2007-1-10)
关键词
小肠结肠炎
坏死性
动物模型
双歧杆菌
干预研究
细胞凋亡
Necrotizing enterocolitis
Neonate
Rat
Bificobacterium longum
Intervention study
Apoptosis
