基于E2相关的小胶质细胞极化探索逍遥散对雌性IBS模型内脏痛觉过敏的机制

Irritable bowel syndrome (IBS) is often accompanied by visceral hypersensitivity such as abdominal pain. The incidence in female individuals is higher than that of male, and the females are much more susceptible than the males due to early life adversity (ELA). There are quite a lot of drugs for IBS, but the specific clinical drugs for female patients are still lacking. Previous research findings of our group together literature review suggest that estradiol (E2)-dependent activation of central microglia (MC), and polarization of M1 and M2 may be the mechanism of Xiaoyao San (XYS) for improving hyperalgesia in female IBS models..The current project will elucidate the roles for XYS in “ E2-dependent central MC polarization "approach by establishing the female unpredictable ELA-related IBS model in vivo, and by polarization stimulation to MC after E2 long exposure in vitro. The key linking points are possibly related to adjusting E2 receptor, TLR4, IL-4R or PI3K/Akt pathway, promoting M1 to M2 polarization and improving central inflammation which give rise to visceral hyperalgesia..This study will clarify the role of XYS in treatment of IBS from a new perspective, expanding the research connotation, providing the meaningful scientific basis for clinical study of female IBS patients and clinical application of XYS.

肠易激综合征（IBS）常伴有腹痛等内脏高敏感，女性发病率高于男性，并易受早期生活逆境（ELA）影响。治疗本病药物种类不少，但临床缺乏针对女性患者的有效药物。课题组前期研究成果和文献研究表明，雌二醇（E2）依赖的中枢小胶质细胞（MC）激活、M1和M2型极化可能是逍遥散（XYS）改善雌性IBS模型内脏痛觉过敏的机制。.本课题通过体内不可预测ELA建立雌性IBS模型和体E2长期暴露后极化刺激MC模型等手段，阐明XYS作用于“E2相关的中枢MC极化”途径，其关键点可能与调节E2受体、TLR4、IL-4R或PI3K/Akt途径有关，促进M1向M2极化平衡，改善中枢炎症引发的内脏痛觉过敏。.本研究从新的角度阐述XYS治疗IBS的作用，拓展了XYS的研究内涵，为女性IBS研究和XYS的临床应用，提供有意义的科学依据。

体内实验中，本研究通过雌性大鼠慢性不可预知性应激（Chronic unpredictable stress, CUS）建立了雌性大鼠内脏痛觉过敏的IBS模型，并出现脊髓后角的星状胶质细胞GFAP表达增加。逍遥散（Xiao-yao San，XYS）可改善模型痛觉过敏、排便异常，对脊髓后角内小胶质细胞数量改变不明显，但可降低脊髓后角的星状胶质细胞GAFP的表达。细胞实验中，发现XYS中的君药柴胡的主要有效成分柴胡皂苷D（Saikosaponin D, SSd）通过雌激素受体β（estrogen receptor β，ERβ），抑制脂多糖（Lipopolysaccharide，LPS）激活的N9细胞NFκb经典炎症通路。本研究还揭示了雌性大鼠卵巢切除（ovariectomy，OVX）联合CUS模型的行为学特征，发现后者比单纯OVX或CUS有更显著的焦虑抑郁样行为，且排便增多，前额叶皮质（prefrontal cortex，PFC）内小胶质细胞Iba-1表达显著增多，海马内星状胶质细胞显著增多。XYS作用后可减少OVX联合CUS模型的焦虑抑郁行为，且减少海马星状胶质细胞水平进而改善海马内炎症，减少海马神经元的损伤。研究还证实，单纯OVX大鼠出现空间和情景记忆的缺失，伴随海马神经元树突棘缺失或密度减少。XYS有类似雌激素作用，通过增加海马E2水平，进而增加NMDA受体(N-methyl-D-aspartic acid receptors，NMDARs)表达激活，提高OVX模型的记忆水平，提高海马神经元棘突密度，减少海马神经元凋亡。研究还发现OVX雌性大鼠出现肝脏脂肪变性，肝脏功能异常、脂肪代谢紊乱， XYS可改善OVX大鼠的肝功能和脂肪代谢紊乱，改善肝脂肪变性。