School of Chinese Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong.
Phytomedicine. 2012 Mar 15;19(5):402-8. doi: 10.1016/j.phymed.2011.11.013. Epub 2012 Jan 9.
Visceral hypersensitivity is an important characteristic feature of functional gastrointestinal disorders, such as irritable bowel syndrome (IBS). This study evaluated the effect of Schisandra chinensis on visceral hyperalgesia induced by neonatal maternal separation (NMS) in an IBS rat model. The visceromotor responses to colorectal balloon distension (CRD) were measured by abdominal withdrawal reflex (AWR) and electromyographic (EMG) activities. NMS control rats (receiving vehicle) underwent aggravated visceral pain in response to CRD as compared to normal rats, evidenced by the reduced pain threshold, enhanced AWR scores and EMG responses. Treatment with a 70% ethanol extract of S. chinensis (0.3g/kg and 1.5g/kg/day) for 7 days resulted in an increase in the pain threshold (NMS control: 19.1±1.0mmHg vs low-dose: 24.8±1.3mmHg and high-dose: 25.2±1.8mmHg, p<0.01), and abolished the elevated AWR and EMG responses to CRD in NMS rats (AUC values of EMG response curve were: 1952±202 in NMS control group vs 1074±90 in low-dose group and 1145±92 in high-dose group, p<0.001), indicating that S. chinensis could reverse the visceral hypersensitivity induced by early-life stress event. The result of ELSA measurement shows that the elevated serotonin (5-HT) level in the distal colon of NMS rats returned to normal level after treatment with S. chinensis. Moreover, the increase in pain threshold in rats treated with S. chinensis was associated with a decline of the mRNA level of 5-HT(3) receptor in the distal colon. All available results demonstrate that S. chinensis can reverse visceral hypersensitivity induced by neonatal-maternal separation, and the effect may be mediated through colonic 5-HT pathway in the rat.
内脏敏感性是功能性胃肠疾病（如肠易激综合征（IBS）的重要特征。本研究评估五味子对 IBS 大鼠模型中新生儿母体分离（NMS）引起的内脏高敏的影响。通过腹壁回缩反射（AWR）和肌电图（EMG）活动测量对结直肠球囊扩张（CRD）的内脏运动反应。与正常大鼠相比，接受载体的 NMS 对照大鼠对 CRD 的内脏疼痛加剧，表现为疼痛阈值降低、AWR 评分和 EMG 反应增强。用五味子的 70%乙醇提取物（0.3g/kg 和 1.5g/kg/天）治疗 7 天导致疼痛阈值增加（NMS 对照：19.1±1.0mmHg 与低剂量：24.8±1.3mmHg 和高剂量：25.2±1.8mmHg，p<0.01），并消除了 NMS 大鼠对 CRD 的升高的 AWR 和 EMG 反应（EMG 反应曲线的 AUC 值：NMS 对照组为 1952±202，低剂量组为 1074±90，高剂量组为 1145±92，p<0.001），表明五味子可以逆转早期生活应激事件引起的内脏高敏性。ELSA 测量结果表明，NMS 大鼠远端结肠中升高的 5-羟色胺（5-HT）水平在用五味子处理后恢复正常水平。此外，用五味子治疗的大鼠疼痛阈值升高与远端结肠 5-HT（3）受体 mRNA 水平下降有关。所有可用结果表明，五味子可以逆转新生儿母体分离引起的内脏高敏性，其作用可能通过大鼠结肠 5-HT 途径介导。
