肠易激综合征内脏高敏模型不同制作方法的比较研究

Methods for establishing rat models of irritable bowel syndrome visceral hypersensitivity

目的研究不同方法制作IBS内脏高敏幼鼠模型,并对其内脏敏感性及稳定性进行评价。方法将出生后第2天的SD大鼠幼鼠随机分成母婴分离组(A组)、不可预测性母婴分离组(B组)和空白对照组(C组)。造模成功后,观察大鼠一般情况及大便情况,并通过腹壁撤退反射(abdominal withdrawal reflex,AWR)评分和内脏痛阈值测定大鼠内脏高敏性及持续性,检测结束后,取大鼠结肠组织进行病理检测。结果各组间体重、结肠病理组织检测无显著差异(P> 0.05);与A组和C组比较,B组大鼠大便颗数增多、粪便含水量增加;与C组相比,A组及B组大鼠的AWR评分更高,且在9周龄时达到峰值,而在11周龄,A组及B组大鼠AWR评分较之前降低;在5~9周龄期间,与C组比较,A组和B组引起的内脏痛阈值更低。结论母婴分离和不可预测性母婴分离均可模拟出IBS内脏高敏性模型,其中不可预测性母婴分离模型更适合制作腹泻型IBS模型。同时,IBS内脏高敏存在时间依赖性,模型稳定期多为造模结束后到大鼠9周龄以内。

Objective To assess visceral hypersensitivity and constancy of visceral hypersensitivity models of irritable bowel syndrome( IBS) in rats. Methods Two-day-old Sprague-Dawley rat pups were randomly divided into the neonatal maternal separation group( group A),the unpredictable neonatal maternal separation group( group B),and the control group( group C). After successful modeling,the rats’ general conditions and stools were observed,and their visceral hypersensitivity and constancy were determined via the abdominal wall withdrawal reflex and visceral pain threshold. After testing,the rats’ colonic tissue was taken for pathological examination. Results Body weight and colonic pathological examinations did not differ between the groups( P> 0. 05). Compared with groups A and C,rats in group B had increased stools and stool water content. Compared with groups B and C,the abdominal withdrawal reflex( AWR)threshold was highest in the group A rats and peaked at 9 weeks of age. The visceral pain threshold did not differ between groups A and B but was lower in both groups compared with that of group C( P > 0. 05). Conclusions Both the neonatal maternal separation and the unpredictable neonatal maternal separation models simulated the IBS visceral hypersensitivity model. The unpredictable neonatal maternal separation model better simulated a diarrheal IBS model. The visceral hypersensitivity model was time-limited,and the optimal experimental time was within 9 weeks of age.