天然蒙脱石对新生鼠坏死性小肠结肠炎肠损伤及肠组织sPLA2的影响

目的：探讨添加天然蒙脱石对新生鼠坏死性小肠结肠炎（N EC ）模型肠损伤保护作用及对肠组织中分泌型磷脂酶A2（sPLA2）含量变化的影响，为预防性应用天然蒙脱石防治 NEC提供依据。方法新生SD大鼠出生后48 h开始给予鼠配方奶喂养，100％氮气缺氧90 s ，4℃冷刺激10 min ，每天2次，连续3 d ，建立新生鼠NEC模型。按析因设计，32只新生SD大鼠分成4组，A1 B1组为NEC模型组，在出生48 h起每日给予天然蒙脱石灌胃，剂量为0．6 g · kg -1· d-1，每日3次；A1 B2组为N EC模型组，未添加天然蒙脱石；A2 B1组为对照组，给予天然蒙脱石灌胃，每日3次，0．6 g · kg -1· d-1；A2 B2组为对照组，未添加天然蒙脱石。每组动物各8只。在最后一次缺氧、冷刺激后24 h空腹断头处死大鼠，留取十二指肠下端至直肠上端肠管进行肠组织损伤评分和肠组织中sPL A2含量检测。肠损伤组织学评分≥2确定为 NEC ；新生鼠肠组织中 PLA2含量采用 ELISA 双抗体夹心法检测。应用Kruskal-Wallis H检验和析因设计的方差分析进行统计学分析，α＝0．05为显著性检验标准。结果 A1B1组、A1 B2组新生SD大鼠出现腹泻、腹胀、萎靡、活动减少、生长减慢，A1 B1组程度较轻。A1 B2组肠组织损伤评分和肠组织中PLA2含量显著高于A2B2组、A2B1组；与A1B2组相比，A1B1组肠损伤组织评分明显降低，肠组织中 PLA2含量亦明显减少，但仍高于A2 B1组、A2 B2组；在控制造模因素后，添加天然蒙脱石组和没有添加天然蒙脱石组肠损伤组织评分的边缘估计均值及95％ CI为：0．79（0．62，0．96），1．83（1．67，2．00），PLA2含量边缘估计均值及95％ CI分别为：0．785（0．581，0．990），1．159（0．954，1．364），差别均有统计学意义。结论添加天然蒙脱石可降低N EC新生大鼠肠损伤程度，降低其肠组织中PL A2含量。

Effects of Smectite Power on Neonatal Rat Model of Necrotizing Enterocolitis and Roles of Secretory Phospholipase A2

Objective To explore the protective effects and the mechanism of smectite powder in inhibit intestinal injury of neonatal SD rat necrotizing enterocolitis （NEC） model . Methods According to 2 × 2 factor analysis ,32 neonate SD rats （48 hours olds ,weighing 5~10 g ） were divided into 4 groups （A1B1 ,A1B2 ,A2B1 and A2B2 ,n=8 rats each groups） . Rats in group A1 B1 and A1 B2 were made into NEC models as follows ：separate from mother rats and feeding with rat milk substitute ,hypoxia（100%N2 ） for 90 second and 4 ℃ cold exposure for 10 minutes ,twice a day during 3 consecutive days . Rats in group A1B1 was given smectite powder （0 .6 g · kg -1 · d-1 ） and rats in group A1 B2 was not . Rats in groups A2B1 and A2B2 served as control groups ,as well as rats in group A2B1 was given smectite powder （0 .6 g · kg -1 · d-1 ） and those in group A2B2 was not . On the 4th day all the subjects were sacrificed and intestinal tissues were obtained to examine . The intestine around ileocecal junction was for histological analysis and score . The mean scores more than 2 were considered NEC . The remaining intestine was used to measure the contents of secretory phospholipase A 2 （sPLA2 ） in homogenate of intestinal tissue by ELISA ,and were expressed pg per mg protein of intestinal tissue . Kruskal-Wallis H test and factorial ANOVA were used to analyze difference among various groups . α=0 .05 was considered significant . Result Neonatal rats in groups A1B1 and A1B2 had diarrhea ,abdominal distention ,growth and develop-ment stepping down ,activity reducing . As compared with group A1B2 ,there were remarkably relieved after given smectite powder in group A1B1 . The score of histopatholigical and the content of sPLA2 in in-testinal tissue had significant difference among groups . Comparing with that of group A1B2 ,the score of histopatholigical and the content of sPLA2 in intestinal tissue of group A1 B1 reduced ,but that of group A1B1 was higher than two control groups significantly . By factorial