幼鼠慢性内脏高敏感模型的建立及评价

目的探讨新生期母婴分离（NMS）建立幼年慢性大鼠内脏高敏感模型的可能性及意义。方法 30只新生大鼠随机分成3组,A组出生后第2-14天每天与母鼠分离3 h（8∶00-11∶00）,连续13 d;B组为出生后第2-21天每天与母鼠分离3 h（8∶00-11∶00）,连续20 d;C组不予任何处理,与母鼠同笼。随后,3组大鼠常规饲养。6周龄时采用腹壁撤退反射（AWR）,肌电痛阈测定评估其内脏敏感性。结果与C组比较,A组、B组幼鼠AWR评分、腹外斜肌放电波幅值明显升高,痛阈明显降低;A组和B组组间幼鼠AWR评分、腹外斜肌放电波幅值及痛阈差异无显著性意义;3组幼鼠间玻璃小球排出时间及粪点数差异无统计学意义。结论持续的新生期母婴分离可建立一种没有明显肠道动力学改变的幼鼠慢性内脏痛模型。

Establishment and Evaluation of a Model of Visceral Hyperalgesia in Young Rats

Objective To establish and evaluate in young rats a model of visceral hyperalgesia induced by maternal separation（MS） stimulation in the neonatal period.Methods Thirty Sprague-Dawley rats of two days old were divided randomly into NMS39,NMS60 and control groups.Baby rats were separated from their mothers for 3 h/d（8∶00-11∶00 am） during postnatal days 2～14 in the NMS39 group and during postnatal days 2～21 in the NMS60 group while those in the control group always lived with their mothers during postnatal days 2～21.The visceral sensitivity of six-week-old rats was evaluated by the score of abdominal withdrawal reflex（AWR）,the amplitudes of spike of external oblique muscle of abdomen（EOMA） and visceral pain threshold.The amount of fecal pellets and the time of glass pellets output in the young rats were observed.Results Compared with the control rats,young rats in the NMS39 and NMS60 group showed a significant increase in the score of AWR and the amplitudes of spike of EOMA and a remarked decrease in the pain thresholds.But the comparison between the NMS39 and NMS60 group revealed no significant differences in the above indexes.The comparison among the three groups reported no significant differences in fecal pellets and the time of glass pellets output.Conclusion The persistent MS in neonatals can result in chronic visceral hypersensibility in young rats.