胃癌 Open Access
Copyright ©The Author(s) 2003. Published by Baishideng Publishing Group Inc. All rights reserved.
世界华人消化杂志. 2003-01-15; 11(1): 22-24
在线出版日期: 2003-01-15. doi: 10.11569/wcjd.v11.i1.22
根除幽门螺杆菌对胃癌前病变组织中bax蛋白表达的影响
刘海峰, 刘为纹, 房殿春, 王国安, 滕小春
刘海峰, 刘为纹, 房殿春, 王国安, 滕小春, 中国人民解放军第三军医大学西南医院全军消化内科中心 重庆市 400038
刘海峰, 男, 1965-11-06生, 河北省景县人, 汉族. 1988年毕业于第三军医大学, 1994年和1998年分别获得第三军医大学医学硕士和医学博士学位, 副教授, 副主任医师, 硕士研究生导师, 目前主要从事胃癌的发病机制及其防治研究, 发表论文52篇, 获军队科技进步二等奖1项, 主编医学专著1部, 参编医学专著6部.
基金项目: 军队医药卫生"九五"重点课题资助项目, No. 96Z047及重庆市应用基础研究基金资助项目.
通讯作者: 刘海峰, 400038, 重庆市沙坪坝区高滩岩正街30号, 中国人民解放军第三军医大学西南医院消化科. hfliuwz@163.net
电话: 023-65318301-73055
收稿日期: 2002-07-31
修回日期: 2002-08-05
接受日期: 2002-08-16
在线出版日期: 2003-01-15

目的: 研究H. pylori感染及根除治疗对胃癌前病变组织中促凋亡基因Bax蛋白表达的影响, 探讨H. pylori的致病机制及其在胃癌发生中的作用.

方法: 采用快速尿素酶试验、Warthin-starry银染色检测H. pylori; 采用免疫组织化学SP法检测72例胃癌前病变组织中Bax蛋白的表达情况, 以及H. pylori阳性患者H. pylori根除前后胃癌前病变Bax蛋白表达的变化.

结果: Bax蛋白在肠上皮化生及不典型增生组织中均有不同程度的表达, 其阳性表达率为63.9%. H. pylori阳性胃癌前病变组Bax蛋白阳性表达率(72.3%)显著高于H. pylori阴性胃癌前病变组(48.0%, x2 = 4.191, P<0.05), H. pylori感染与Bax阳性表达及分级呈正相关(r = 0.978, P<0.01). 经三联治疗根除H. pylori后, Bax蛋白阳性表达率(70.3%)较治疗前显著降低(43.2%, x2 = 5.506, P<0.05), 而H. pylori仍为阳性者Bax蛋白阳性表达率则无变化.

结论: H. pylori感染可以促进促凋亡基因Bax蛋白的表达, 这可能是H. pylori感染诱导胃黏膜上皮细胞凋亡的主要机制之一, 从而导致细胞凋亡和增生的调节紊乱, 使胃黏膜上皮不稳定性增加, 使其具有较高的癌变易感性. 根除H. pylori感染可纠正Bax基因表达的异常, 对预防或减缓胃癌的发生可能具有重要意义.

关键词: N/A

引文著录: 刘海峰, 刘为纹, 房殿春, 王国安, 滕小春. 根除幽门螺杆菌对胃癌前病变组织中bax蛋白表达的影响. 世界华人消化杂志 2003; 11(1): 22-24
Effect of Helicobacter pylori infection on bax protein expression in patients with gastric precancerous lesions
Hai-Feng Liu, Wei-Wen Liu, Dian-Chun Fang, Guo-An Wang, Xiao-Chun Teng
Hai-Feng Liu, Wei-Wen Liu, Dian-Chun Fang, Guo-An Wang, Xiao-Chun Teng, Department of Gastroenterology, Southwest Hospital, Third Military Medical University, Chongqing 400038, China
Supported by: the fund for Key Projects in the Army Medical and Health 9th 5-year Plan, and by the fund for Chongqing applied base research.
Correspondence to: Dr. Hai-Feng Liu, Department of Gastroenterology, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Zhengjie, Shapingba District, Chongqing 400038, China. hfliuwz@163.net
Received: July 31, 2002
Revised: August 5, 2002
Accepted: August 16, 2002
Published online: January 15, 2003

AIM: To evaluate the effect of Helicobacter pylori (H. pylori) infection on bax protein expression, and explore the role of H. pylori in the development of gastric carcinoma.

METHODS: H. pylori was examined by rapid urease test and Warthin-Starry method, and bax protein was examined by immunohistochemical staining in 72 patients with pre-malignant lesions.

RESULTS: Bax protein was expressed with different degree in intestinal metaplasia and gastric dysplasia, its positive rate being 63.9%. The positive rate of Bax protein expression in H. pylori-positive gastric precancerous lesions (72.3%) was significantly higher than that in H. pylori-negative gastric precancerous lesions (48.0%, x2 = 4.191, P < 0.05). H. pylori infection was correlated well with the expression of Bax protein in gastric precancerous lesions(r = 0.978, P < 0.01). After eradication of H. pylori, the positive rate of bax protein expression was significantly decreased in H. pylori-positive gastric precancerous lesions(x2 = 5.506, P < 0.05). In the persistent H. pylori infected patients, the positive rate of Bax protein expression was not changed.

CONCLUSION: H. pylori is involved in the expression of Bax gene. H. pylori infection increases the expression of Bax protein, this may be one of the mechanisms of H. pylori infection in the induction of gastric epithelial cell apoptosis. H. pylori might act as a tumor promoter in the genesis of gastric carcinoma. Eradication of H. pylori could inhibit the formation and development of gastric carcinoma.

Key Words: N/A


0 引言

大量的流行病学资料表明, 胃癌发生率与当地的幽门螺杆菌(Helicobacter pylori, H. pylori)感染率呈正相关, H. pylori感染者发生胃癌的危险性较非感染者高6倍[1-10]. 从慢性浅表性胃炎、萎缩性胃炎、肠上皮化生及异型增生到胃癌的演变过程已经明确. H. pylori感染为慢性胃炎的主要病因, 因此有理由认为H. pylori感染是胃癌发生的危险因素之一[11-18]. 但其确切的致病机制尚不完全清楚. 已有研究表明, H. pylori可能通过某些环节造成胃黏膜组织癌基因的突变、细胞信号转导异常等导致胃黏膜细胞发生癌前变化. 但通过研究胃癌前病变组织中H. pylori感染及根除治疗对Bax蛋白表达的影响来探讨H. pylori致病机制的报道少见. 为进一步探讨H. pylori在胃癌发生过程中的作用, 我们对H. pylori根除前后胃癌前病变组织中 Bax表达的变化进行了研究.

1 材料和方法
1.1材料

我院1994/1996年胃镜活检标本72例. 其中肠上皮化生51例, 中、重度异型增生21例. 胃镜活检标本均取自胃窦部. 组织标本经40 g/L甲醛固定, 石蜡包埋, 4 mm厚连续切片, 并经HE染色病理诊断证实. H. pylori检测采用快速尿素酶试验和Warthy-starry银染色, 两项均阳性者为H. pylori阳性, 两项均阴性者为H. pylori阴性, 单项阳性者退出试验. 对H. pylori阳性者给予有机铋剂、羟氨苄青霉素、灭滴灵三联药物进行治疗, 疗程为2 wk. 治疗结束后复查胃镜, 停药4 wk后H. pylori仍保持阴性者为H. pylori根除.

1.2方法

Bax蛋白表达的检测采用SP法. Bax多克隆抗体为美国Dako公司产品, 免疫组化试剂盒(Immunostain SP Kit)为美国Santa Cruz公司产品. 染色程序按SP法操作常规进行. 以PBS代替一抗为阴性对照, 以已知Bax蛋白阳性的胃癌组织为阳性对照. 光镜下观察Bax蛋白免疫组化染色切片的显色反应, 数5个以上高倍视野, 不少于400个胃黏膜上皮细胞. Bax结合染色反应深度及阳性细胞数分为0-3四级:(-)无阳性反应细胞、阳性细胞<10%或背景同空白对照者; (+)10%-25%细胞明显阳性, 或大多数细胞弱阳性; (++)26%-50%的细胞明显阳性; (+++)>50%的细胞明显阳性.

统计学处理 Stata 软件包的x2检验, Fisher精确检验, 有序的Logistic回归. P<0.05有统计学意义.

2 结果

在51例肠化生组织中, H. pylori阳性35例, H. pylori阴性16例, H. pylori感染率为68.6%.21例中、重度异型增生组织中, H. pylori阳性12例, H. pylori阴性9例, H. pylori感染率为57.1%. 肠化生与异型增生组织中H. pylori感染率无显著性差异.

Bax蛋白阳性反应物质呈棕黄色, 主要位于腺上皮细胞质内, 偶可伴胞核着色(图1). Bax蛋白在肠化生和异型增生组织中均有不同程度的表达, 其阳性表达率为63.9%. H. pylori阳性组胃癌前病变Bax蛋白阳性表达率为72.3%, 显著高于H. pylori阴性组(48.0%, P<0.05). H. pylori感染与Bax阳性表达及分级呈正相关(P<0.01, Logistic回归分析, 表1).47例H. pylori阳性患者经前述三联药物治疗后, 37例H. pylori被根除, 10例仍为H. pylori阳性. H. pylori根除组胃癌前病变Bax蛋白阳性表达率为43.2%, 较治疗前显著降低(70.3%, P<0.05), 而H. pylori仍为阳性组胃癌前病变Bax蛋白阳性表达率(40.0%)与治疗前无变化.

表1 H. pylori感染与胃癌前病变Bax蛋白表达的关系.
H. pylorinBax阳性分级
Bax阳性率(%)
-++++++
阳性47131510972.3a
阴性251364248.0
图1
图1 肠化生组织, Bax蛋白阳性反应物质呈棕黄色SP×200.
3 讨论

胃癌发生发展过程中不仅存在细胞的过度增生, 而且存在细胞凋亡的异常, 细胞凋亡与细胞增生平衡失调是胃癌发生的病理学基础[19-28]. H. pylori是胃癌的第一类致病因子, 其在胃癌发生中的作用已被广泛关注[1,2,8-14]. 我们以往的研究工作发现, H. pylori感染不仅可以刺激胃黏膜上皮细胞过度增生, 也可以诱导胃黏膜上皮细胞凋亡, H. pylori感染是引起胃黏膜上皮细胞增生和凋亡异常的重要机制之一; H. pylori感染后使胃黏膜上皮细胞增生和凋亡均明显增加, 必然会导致胃黏膜上皮细胞增生与凋亡的调节紊乱, 使胃黏膜上皮细胞不稳定性增加, 从而增加患胃癌的危险性[20,23,24,28]. 但是, H. pylori感染诱导胃黏膜上皮细胞凋亡及促进胃黏膜上皮细胞过度增生的机制目前尚不清楚.

Bax是编码Bcl-2相关X蛋白(Bcl-2 associated X protein, Bax)的基因. Bax蛋白与Bcl-2蛋白有21%的同源性, 具有对抗Bcl-2蛋白抑制细胞凋亡的作用. 研究发现Bcl-2/Bax两蛋白之间的比例是决定对细胞凋亡抑制作用强弱的关键因素, 因此认为Bax是重要的促细胞凋亡基因之一[29,30]. H. pylori感染是否通过影响Bax基因的表达调控胃黏膜上皮细胞增生和凋亡, 是一个值得探讨的问题, 因此, 我们对胃癌前病变组织中H. pylori感染与Bax蛋白表达的关系进行了研究. 研究发现, Bax蛋白在肠化生和异型增生组织中均有不同程度的表达, H. pylori阳性组胃癌前病变组织中Bax蛋白表达阳性率显著高于H. pylori阴性组, H. pylori感染与Bax阳性表达及分级呈正相关; H. pylori根除组胃癌前病变Bax蛋白阳性表达率较治疗前显著降低, 而H. pylori仍为阳性组胃癌前病变Bax蛋白阳性表达率与治疗前无变化. 表明H. pylori感染可以促进Bax蛋白的表达, 这可能是H. pylori感染诱导胃黏膜上皮细胞凋亡的主要机制, 导致胃黏膜上皮细胞增生与凋亡的调节紊乱, 从而使胃黏膜上皮细胞易于向恶性转化. 其原因可能是H. pylori感染继发炎症过程中释放多种细胞因子、自由基和一氧化氮, 这些物质可引起染色体损伤、基因突变; 也可能是H. pylori自身及其代谢产物有潜在的致癌活性[31-34].

本研究结果提示, 对有H. pylori感染的胃癌前病变患者, 应积极抗H. pylori治疗, 可能会促使Bax基因异常表达的逆转, 从而纠正细胞凋亡、细胞增生的异常, 可能具有降低患胃癌的危险性, 预防或减缓胃癌发生的重要作用. 以上推论尚需临床观察验证.

编辑: N/A

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