胃癌腹腔转移对腹腔微环境改造致胃肠动力障碍机制的研究

Slowing down of gastrointestinal peristalsis is a fatal complication of gastric cancer peritoneal metastasis to accelerate the cachexia occurred. In the preliminary experiments on a mouse model for GCPM, we found that the number of ICC (interstitial cells of Cajal)decreased, the cells occurred pyknosis and gap junction disappeared. The electrophysiological characteristics showed slow wave frequency of small intestine slowed down. The expression of ICC increased and slow wave frequency and amplitude of small intestine increased after SCF or ouabain adminstration. ICC occurred pyknosis after co-cultured with primitive cells and gastric cancer cell, the morphology of ICC and the expression rate were ameliorated after SCF treatment.Our study firstly put forward slowing down of gastrointestinal peristalsis induced by GCPM was related with abnormal ICC in small intestine. But, the mechanism of ICC damage is unclear now. Our study put forward the hypothesis: tumor related macrophages in the tumor maybe the major reason of ICC damage in the host intestine in microenvironment. The ICC reduction, pyknosis, membrane damage, HCN ion channel and SCF/c - kit signal transfer disorder induced slowing down or stagnation of gastrointestinal peristalsis. To verify this hypothesis, our study will explore the pathophysiological mechanisms of ICC injured by tumor associated macrophages through peritoneal fluid from human gastric cancer, the rat model and ICC primary cells with pathology and molecular biology techniques, whereby providing theoretical basis for treatment.

胃癌腹腔转移致胃肠蠕动减慢是致命并发症,加快恶病质发生。前期通过鼠模型研究发现，小肠Cajal间质细胞(ICC)减少固缩，缝隙连接消失，电生理显示小肠慢波频率减慢。干细胞因子/哇巴因干预，ICC表达增多，小肠慢波振幅和频率有提高。小肠原代ICC与胃癌细胞共培养，ICC固缩，加干细胞因子可改善ICC形态和表达率。研究结果首次提出胃癌腹腔转移致胃肠蠕动减慢与小肠ICC损伤有关。但导致ICC损伤机制不清楚。本研究提出假说：肿瘤微环境中的肿瘤相关巨噬细胞可能是造成宿主小肠ICC损伤原因。因ICC减少、固缩，细胞膜受损，HCN离子通道蛋白丢失，SCF/c-kit信息传递障碍，致胃肠蠕动减慢或停滞。为验证这一假说，本研究通过收集胃癌术后腹腔转移的腹腔液体、鼠模型、ICC原代细胞，采用病理学和分子生物学技术，探讨肿瘤相关巨噬细胞对小肠ICC损伤致胃肠蠕动减慢的病理生理机制，寻找治疗新思路而提供理论依据。

胃癌腹腔转移致胃肠蠕动功能障碍，对腹腔晚期恶性肿瘤患者的生存时间和生存质量均造成严重影响，是致命并发症，亦导致临床医生在对晚期恶性肿瘤的诊治方面非常棘手。本研究通过模拟胃癌腹腔转移模型、胃癌晚期伴有腹水的癌组织和腹水液沉淀的肿瘤细胞，通过病理学技术、分子生物学技术等进行了深入研究。结果发现，导致胃肠蠕动功能障碍的病变基础是小肠Cajal间质细胞（ICC）减少、固缩凋亡，与功能性细胞间缝隙连接消失，电生理亦显示小肠慢波频率减慢、波幅变短。体外给予SCF干细胞因子/哇巴因干预，小肠ICC表达的数目增多，小肠慢波振幅和频率都有提高。体外小肠ICC原代培养及与胃癌细胞共培养，小肠ICC固缩，加SCF后，可改善小肠ICC形态和其表达率。同时，癌性腹水上清液与小肠ICC共培养，免疫荧光检测HCN2（ICC细胞表面离子通道蛋白），共培养组HCN2荧光表达与对照组相比强度减弱，细胞结构不清。加入SCF后，HCN2荧光表达有所升高，细胞形态有所恢复。首次提出胃癌腹腔转移致胃肠蠕动减慢与小肠ICC损伤有关。胃癌腹腔转移改变了腹腔的造成宿主小肠ICC损伤、减少、固缩，细胞膜受损，HCN离子通道蛋白丢失，SCF/c-kit信息传递障碍，最终导致胃肠蠕动减慢或停滞。这是胃肠蠕动减慢的病理生理学机制。在此基础上，对卵巢癌腹水沉淀细胞成分的进行了鉴定。结果提示，未化疗的肿瘤细胞体积大，核大、异型性明显，胞突增多，胞浆中细胞骨架成分明显的增多，细胞器丰富，有的肿瘤细胞成团生长；化疗后的肿瘤细胞多数呈坏死或凋亡改变，核变空或核小体形成等。体外选择了SKOV3浆液性卵巢癌细胞腹水共培养，倒置显微镜下见SKOV3细胞密集排列，多呈圆形或略呈椭圆形，电镜下细胞核小体多、明显，胞质见散在的脂滴，胞膜较多纤细的突起。第3天见肿瘤细胞生长更加密集，个别细胞呈梭形，电镜下细胞呈椭圆形，核增大，胞核比值亦增大。第5天见肿瘤细胞数量略减，但肿瘤细胞彼此间连接增多，细胞呈纤细状或梭形，电镜下局灶性的细胞间连接增多。对卵巢癌腹水沉淀细胞的自噬/凋亡相关指标的检测发现，未化疗的腹水沉淀细胞，自噬表达增强，凋亡减少，而化疗后的腹水沉淀细胞自噬表达减弱，凋亡表达增强。上述研究结果进一步验证了，对卵巢癌腹水最佳的治疗首选仍是化疗，可降低自噬、促进凋亡，达到治疗的目的。