论文部分内容阅读
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 investigate the protective effect of Bifidobacterium on intestinal damage induced by necrotizing enterocolitis (NEC) in neonatal rats. Methods Thirty-two newborn SD rats were randomly divided into 4 groups according to factorial design, with 8 animals in each group. A1B1 group was NEC model group with Bifidobacterium (109CFU / d), A1B2 group was NEC model group but no Bifidobacterium was added; A2B1 group was control group with bifidobacterium (109CFU / d), A2B2 group was Control group, and did not add bifidobacteria. The model rats were fed with artificial milk for 48 h after birth, hypoxia was induced by 100% nitrogen for 90 seconds, cold stimulation at 4 ° C for 10 minutes, and twice daily for 3 days. Neonatal rat model of NEC was established. Mice were sacrificed 24 h after fasting and decapitated, and the lower intestine of duodenum was taken for dissection. The pathological examination and intestinal injury score were performed on the proximal intestine of the ileocecal part. The histological score≥2 was NEC , The other intestine intestinal apoptosis rate detection and electron microscopy. The apoptosis rate of intestinal cells was detected by flow cytometry. SPSS 11.0 statistical software for statistical analysis, α = 0.05 for the significance test. Results After model establishment, diarrhea, abdominal distension, slowed growth and decreased activity were observed in group A1B1 and group A1B2. Intestinal mucosa necrosis, submucosal hemorrhage and muscular layer necrosis were observed under microscope. The intestinal mucosa appeared by transmission electron microscope A large number of apoptotic cells, the formation of apoptotic bodies, but the A1B1 group lighter. The histological scores (x ± s) of intestinal injury in A1B1, A1B2, A2B1 and A2B24 groups were 2.04 ± 0.52, 3.38 ± 0.55, 0.33 ± 0.36 and 0.38 ± 0.33 respectively, and the apoptosis rates of intestinal cells were (23.97 ± 10.48)%, (47.28 ± 21.98)%, (11.42 ± 4.75)% and (12.16 ± 4.95)%, respectively. There were significant differences in intestinal injury score and intestinal apoptosis rate between groups <0.01). Compared with A1B2 group, the scores of intestinal injury and intestinal cell apoptosis in A1B1 group were significantly lower than those in A1B2 group (P <0.01), but were still higher than those in A2B1 and A2B groups (all P <0.01) , The rate of apoptosis of intestinal cells were affected by NEC modeling and the addition of Bifidobacterium two factors, there is an interaction between NEC modeling and Bifidobacterium supplementation. Conclusion Bifidobacterium can reduce the degree of intestinal damage in neonatal rats with NEC, which may reduce the risk of NEC in neonatal rats by inhibiting the apoptosis of intestinal epithelial cells.