雌激素对大鼠内脏痛觉感受及结肠5-羟色胺合成的影响

EFFECTS OF ESTROGEN ON THE VISCERAL PAIN SENSITIVITY AND COLONIC 5-HT SYNTHESIS IN RATS

目的:研究雌激素对大鼠内脏痛觉感受及结肠5-羟色胺(5-hydroxytryptamine,5-HT)合成的影响。方法:Wistar雌性大鼠采用随机数字表分组,分为假手术组,卵巢切除组及卵巢切除+雌激素组。卵巢切除+雌激素组动物皮下注射苯甲酸雌二醇(30μg·kg^(-1)),连续给药2周。给药结束后次日测定大鼠内脏痛阈值、血清雌激素和孕激素水平;收集结肠组织测定5-HT含量、嗜铬细胞数量及色氨酸羟化酶的表达。结果:雌激素替代给药后显著提高卵巢切除大鼠血清雌激素水平、降低内脏痛阈值、明显提高结肠嗜铬细胞数量、5-HT含量及色氨酸羟化酶的表达。结论:雌激素对结肠5-HT合成具有正性调控作用,该机制可能参与雌激素介导的内脏痛觉感受增强。

Objective：To investigate the effects of estrogen on visceral pain sensitivity and colonic 5-hydroxytryptamine （5-HT） synthesis in rats. Methods： Female Wistar rats were randomly divided and received ovariectomy （OVX） or sham operation. Three groups were set for this study, they are sham group, OVX group and OVX plus estrogen supplementation group. Rats in OVX group and sham group were treated with pure sesame oil subcutaneously as controls, and rats in OVX plus estrogen group were subcutaneously treated with estradiol benzoate （30 ug？kg-1）, drugs were given to rats for consecutive 2 weeks. After drugs treatment, pain threshold pressure was measured by abdominal withdrawal reflex test; blood was collected for determination of the serum level of estrogen and progesterone by ELISA; and proximal colon tissue was also collected for 5-HT content assay, enterochromaffin cells counting, and tryptophan hydroxylase （TPH） expression detection by ELISA, immunohistochemistry and Western-blot, respectively. Results： Compared with the rats in OVX group, the pain threshold in estrogen-treated rats was marked decreased, while colonic enterochromaffin cells density, 5-HT content as well as TPH expression were all significantly increased. Conclusion： Estrogen can positively regulate colonic 5-HT synthesis, and this effect may have correlation with estrogen-mediated increase of visceral sensitivity.