肠易激综合征模型大鼠5-羟色胺7受体的表达及作用

目的 观察5-羟色胺7受体在肠易激综合征(IBS)不同亚型模型大鼠大脑和消化道组织中表达和分布的差异,探讨其在IBS发病中的作用.方法 45只成年SD大鼠分均为对照组、腹泻型IBS(IBS-D)组和便秘型IBS(IB-C)组.乙酸加束缚应激法制备IBS-D模型,冰水灌胃法制备IBS-C模型.免疫组化法和实时定量PCR法检测各组大鼠大脑、空肠、回肠、近端结肠、远端结肠中5-HT7受体的分布及表达差异.放射免疫法测定以上各组织中环磷酸腺苷(cAMP)含量.结果 免疫组化结果 显示,IBS-C组和IBS-D组海马及下丘脑、IBS-C组回肠、近端结肠、远端结肠5-HT7受体表达强于对照组(P＜0.05).实时定量PCR结果 显示,IBS-C和IBS-D组海马和下丘脑、IBS-C组回肠、近端结肠及远端结肠5-HT7受体mRNA明显高于对照组(P＜0.05).IBS-C和IBS-D组海马和下丘脑、IBS-C组近端结肠和远端结肠cAMP含量显著高于对照组(P＜0.05).结论 两组大鼠脑组织及IBS-C大鼠结肠5-HT7受体表达及cAMP水平明显增高,可能与IBS-C胃肠动力障碍和内脏感觉异常有关.

The expression and effect of 5-hydroxytryptamine 7 receptor in brain and intestine of rats with irritable bowel syndrome

Objective To investigate the expression and distribution of 5-hydroxytryptamine 7(5-HT7)receptor in brain and intestine of rats with different subtype of irritable bowel syndrome(IBS).Methods Forty-five SD rats were divided into healthy contral.diarrhea-predominant(IBS-D)and consti pation-predominant(IBS-C)IBS groups.IBS-D and IBS-C models were established by either colonic instillation of acetic acid and restraint stress or stomach irrigation with cool water(0-4℃).The expression and distribution of 5-HT7 receptor at brain and intestine were determined by immunohistochemistry and real-time PCR.The tissue concentration of cyclic AMP(cAMP)was examined by radioimmunoassay.Results Immunohistochemistry study demonstrated that the staining of 5-HT7 receptor at hippocampus and hypothalamus were strong in IBS-C and IBS-D groups compared to control group(P＜0.01),The staining of 5-HT7 receptor at ileum,proximal colon and distal colon were higher in IBS-C group than those in control group(P＜0.05).Real-time PCR revealed that the expression of 5-HT7 receptor at hippocampus and hypothalamus were higher in IBS-C and IBS-D groups than those in control group(P＜0.05).and the expression at ileum and colon were remarkably higher in IBS-C group compared to control group(P＜0.05).The concentration of cAMP at hippocampus and hypothalamus were higher in IBS-C and IBS-D groups than those in control group(P＜0.01,P＜0.05).The cAMP level at proximal and distal colon in IBS-C group was higher than those in control group(P＜0.05).Conclusion The upregulation of 5-HT7 receptor in brain and intestine may be related with the dyskinesis and visceral paresthesia of IBS-C.