高脂饮食诱导肠腺瘤恶变机制研究  

Mechanism of high fat diet enhancing intestinal adenoma-adenocarcinoma sequence

作　　者：刘天宇[1] 曹海龙[1] 董文逍 王斯南[1] 金多晨 郭子宣 黄欣远 王邦茂[1] LIU Tian-yu;CAO Hai-long;DONG Wen-xiao;WANG Si-nan;JIN Duo-chen;GUO Zi-zuan;HUANG Xin-yuan;WANG Bang-mao(Department of Gastroenterology and Hepatology ,General Hospital, Tianjin Medical University, Tianjin 300052, P. R. Chin)

机构地区：[1]天津医科大学总医院消化科,天津300052

出　　处：《中华肿瘤防治杂志》2018年第8期533-539,共7页Chinese Journal of Cancer Prevention and Treatment

基　　金：国家自然科学基金(81570478;81741075);天津市自然科学基金(17JCYBJC24900)

摘　　要：目的肠癌是消化道常见恶性肿瘤之一,越来越多的流行病学研究及动物实验表明高脂饮食(high fat diet,HFD)是肠癌发生的重要危险因素之一。本研究探讨HFD促进肠腺瘤恶变可能的分子机制。方法 4周龄Apcmin/+小鼠分为HFD组和对照组(常规饮食)。12周后处死,观察各组小鼠肠道腺瘤数目、大小及分布。采用HE染色评价腺瘤病理类型及癌变情况,Ki-67免疫组织化学染色评价肿瘤细胞增殖水平,脱氧核苷酸末端转移酶介导的dUTP缺口末端标记法评价细胞凋亡。Real-time PCR和免疫组织化学染色评价单核细胞趋化蛋白-1(monocyte chemoattractant protein-1,MCP-1)及其受体CC趋化因子受体2(CC chemokine receptor 2,CCR2)的mRNA和蛋白表达。免疫荧光双染法检测肠道肿瘤组织中巨噬细胞表面分子F4/80、M1型及M2型肿瘤相关巨噬细胞(tumor associated macrophages,TAMs)表面分子的表达。结果 HFD组肠道腺瘤总数较对照组明显增加(26.60±1.03 vs 10.20±0.92,t=11.90,P<0.001),HFD组60%远段小肠和结肠腺瘤发生粘膜内癌,而对照组腺瘤未见癌变。HFD可增加肠道肿瘤Ki-67阳性细胞百分比[(70.80±7.57)%vs(30.80±5.77)%,t=4.20,P<0.01],降低肿瘤细胞凋亡百分比[(13.00±1.14)%vs(42.60±1.50)%,t=15.69,P<0.001]。HFD组肠道肿瘤组织MCP-1和CCR2 mRNA的表达水平增高,MCP-1及CCR2阳性细胞百分比较对照组明显增加[(73.80±7.02)%vs(36.80±4.68)%,t=4.38,P<0.01;(63.20±2.15)%vs(26.80±2.22)%,t=11.76,P<0.001]。免疫荧光双染提示HFD组肠道巨噬细胞表面分子F4/80和M2型TAMs表面分子MR阳性表达明显增加,M1型TAMs表面分子iNOS阳性表达明显减少。结论高脂饮食可活化MCP-1/CCR2信号通路促进TAMs募集及M2型TAMs极化进而促进Apcmin/+小鼠肠道腺瘤发展成为肠癌。OBJECTIVE The objective of this study was to investigate the effects of high fat diet（HFD） on the in- testinal tumorigenesis and its possible mechanisms. METHODS Four-week-old Apcmin/＋ mice were randomly divided into two groups： HFD group and control group（regular diet）. All mice were killed after 12 weeks. The number, size and lo- cation of intestinal adenoma were observed. The pathological type of adenoma was evaluated after hematoxylin-eosin（HE） staining. Ki-67 expression level was detected by immunohistochemistry（IHC） to evaluate the cell proliferation. Cell apop- tosis was determined by in situ terminal deoxynueleotidyl transferase mediated dUTP nick end labeling technique （TUNEL）. The expression of relative mRNA and protein of MCP-1 and CCR2 were detected by Real-time PCR and IHC. Intestinal tumor associated macrophages（TAMs） were measured by immunofluorescence staining. RESULTS The total number of intestinal adenoma of HFD group was significantly increased, compared with that of control group （26.60±1.03 vs 10.20±0.92, t= 11.90, P〈0. 001）. Pathological analysis confirmed intestinal carcinogenesis in 60% distal segment of small intestine and proximal segment of colon in the HFD group, while there were only adenomas in control group. The elevated positive cells of Ki-67 were observed[（70.80±7.57）% vs （30.80±5.77）%,P〈0.01] ,and the per- centage of cell apoptosis was significantly decreased [（13.00±1.14）% vs （42.60±1.50）%, t= 15.69, P〈0.001] after HFD. The relative mRNA expression levels of MCP-1 and CCR2 dramatically increased in HFD group. The elevated positive cells of MCP-1 and CCR2 were observed in HFD group [（73.80±7.02）% vs （36.80±4.68）%,t=4.38,P〈0.01; （63.20±2.15）% vs （26.80±2.22）%,t= 11.76,P〈0. 001]. Moreover, HFD altered the phenotype of TAMs from M1 to M2. CONCLUSIONS HFD enhanced intestinal adenoma-adenocarcinoma sequence in Apcmin/＋ mice, which may be associated with the recruitment and polarization of M2 TAMs vi

关 键 词：高脂饮食 肠道腺瘤 单核细胞趋化蛋白-1/CC趋化因子受体2 肿瘤相关巨噬细胞 Apcmin/+小鼠 

分 类 号：R735.3[医药卫生—肿瘤]