5-羟色胺对断奶仔鼠应激腹泻的影响

目的探讨断奶仔鼠应激性腹泻发生与5-羟色胺(5-HT)的相关性及断奶仔鼠应激性腹泻的发生机制。方法将72只雄性21 d断奶ICR小鼠随机分为6组,分别为正常对照组、氢溴酸西酞普兰(CH)对照组、对氯苯丙氨酸(PCPA)对照组、应激腹泻组、CH+应激腹泻组及PCPA+应激腹泻组。腹腔注射给药组(CH 10 mg/kg或PCPA 300mg/kg)处理4h后进行应激腹泻处理,即给予番泻叶(0.4 kg/L)按15ml/kg体重灌胃+后肢束缚应激处理(持续4h),其对照组分别给予相同剂量的生理盐水。处理第5天,检测血糖值、小鼠血浆皮质酮(Cort)、5-HT含量和分布的变化。结果与对照组相比,应激腹泻组和CH对照组小鼠血浆和肠道5-HT含量、血糖值和血浆Cort含量升高,腹泻评分增加,但是增重显著减小;CH+应激腹泻组较应激腹泻组相比5-HT含量、血糖值和Cort含量和腹泻评分显著增加,增重显著减小。PCPA对照组5-HT含量显著降低,与正常对照组相比除血浆Cort含量增加以外无显著变化;PCPA+应激腹泻组与应激腹泻小鼠相比肠道5-HT含量显著降低,增重升高,血糖值降低,但未达到正常水平。结论断奶仔鼠应激性腹泻伴随5-HT增加,CH引起的肠道5-HT含量升高直接导致并加重断奶仔鼠应激性腹泻,PCPA诱导的5-HT含量降低可减弱小鼠腹泻程度。

Influence of 5-hydroxytryptamine on stress-induced diarrhea of weaning mice

Objective To investigate the relationship between stress-induced diarrhea and 5-hydroxytryptamine (5-HT) and explore the possible mechanism of stress-induced diarrhea. Methods Citalopram hydrobromide (CH) was used to increase 5-HT content and para-chlorophenylalanine (PCPA) was used to decrease 5-HT intracellular synthesis. Seventy-two male 21 days newly weaned ICR mice were randomly divided into six groups: control, CH group, PCPA group, stress diarrhea group, CH+stress diarrhea group, PCPA+stress diarrhea group. Daily administration of intraperitoneal injection of CH 10 mg/kg or PCPA 300mg/kg, 4 hours later, the last three groups were administrated with intragastric of senna (0.4 kg/L) with 15ml/kg BW dose and hind legs binding stress for 4 hours. The control group was administrated with equal relative doses of saline. Five days later detected blood sugar levels of animals were detected, ELISA and immunohistochemical staining was used to measure 5-HT and corticosterone (Cort) content. Results The data of stress diarrhea and CH treated mice showed an increase in diarrhea score, blood sugar levels and Cort in plasma, but a significant decrease in weight gain coincided with an increase in 5-HT in plasma and intestine compared to that of control animals. Stress diarrhea mice following CH administration showed significantly raised 5-HT in plasma and intestine, which was in coincided with the increased diarrhea score but the greatly decreased weight gain of animals when compared to stress diarrhea mice. Administration of PCPA to mice did not change significantly weight gain and blood sugar levels, but increased Cort content compared to control animals. While treatment with PCPA to stress diarrhea mice resulted in a significantly increase in weight gain and decrease in blood sugar levels, 5-HT, and Cort content compared to stress diarrhea mice, but still was higher than that of control animals. Conclusion 5-HT content in stress diarrhea mice significantly increased, in turn, CH-induced increase of 5-HT content directly resulted in and aggravated stress-induced diarrhea of weaning mice. Conversely, reducing 5-HT content induced by PCPA weakened degree of diarrhea.