目的：

胃癌是我国癌症相关死亡的第三大原因。肿瘤动物模型能够在较大程度上模拟人类肿瘤的多阶段演进过程，弥补因患者个体差异大、难以全程追踪疾病进展的局限性，是肿瘤研究不可或缺的工具。本研究旨在通过联合遗传变异和环境因素建立能够更真实模拟患者肿瘤发生过程的胃癌动物模型，为肿瘤基础和转化研究提供支撑。我们首先分别建立了幽门螺旋杆菌（Helicobacter Pylori, Hp）感染小鼠模型和胃上皮条件性敲除Trp53基因小鼠模型。在此基础上，建立Hp SS1感染联合高盐饮食和Trp53敲除多因素诱导胃癌小鼠模型。

方法：

首先，建立Hp的固体培养和液体培养体系，并确认菌株的稳定性和纯度；评估质子泵抑制剂泮托拉唑对小鼠胃酸分泌的抑制作用，构建Hp感染效率较高的小鼠模型；接着，构建胃特异性Trp53敲除小鼠模型，并进行基因型和表达水平的鉴定；最后，联合Hp感染、Trp53敲除和高盐饮食建立小鼠胃癌模型并进行初步表型鉴定。

结果：

（1）建立Hp体外培养和鉴定体系；

（2）质子泵抑制剂泮托拉唑预处理能够显著抑制胃酸分泌促进Hp体内定植率和克隆数量。

（3）建立Lgr5 CreERT2; Trp53^f/f小鼠，成功实现Trp53基因的条件性敲除。

（4）建立Hp SS1感染联合高盐饮食和Trp53敲除多因素诱导胃癌小鼠模型，5月取材观察到胃萎缩和粘膜溃疡等不良症状。

结论：

成功建立了Hp体外培养和鉴定体系。体内定植实验结果显示质子泵抑制剂预处理能够显著提高Hp体内定植效率。通过建立Lgr5 CreERT2; Trp53^f/f小鼠，成功实现条件性敲除Trp53基因。Hp SS1感染联合高盐饮食和Trp53敲除小鼠模型中观察到胃萎缩和粘膜溃疡等不良症状，但仍需要长期追踪观察明确这些因素的联合处理在胃癌发生发展中的作用。

Objective:

Gastric cancer is the third leading cause of cancer-related deaths in China. Tumor animal models, which can largely mimic the multistage progression of human tumors, help overcome the limitations posed by patient heterogeneity and the difficulty of continuously monitoring disease development. They are indispensable tools for cancer research. This study aimed to establish a gastric cancer mouse model that more accurately simulates the tumorigenesis process in patients by combining genetic alterations and environmental factors, thereby providing a foundation for basic and translational research. We first established mouse models of Helicobacter pylori (Hp) infection and gastric epithelial-specific Trp53 gene knockout. Based on these, we further constructed a multifactor-induced gastric cancer mouse model involving Hp SS1 strain infection, high-salt diet, and Trp53 knockout.

Methods:

We first developed solid and liquid culture systems for the Hp strain and confirmed the stability and purity of the bacterial cultures. The effect of the proton pump inhibitor pantoprazole on gastric acid suppression was evaluated to optimize the conditions for high-efficiency Hp colonization in mice. Subsequently, a gastric epithelium-specific Trp53 conditional knockout mouse model was generated and validated at the genotypic and transcriptomic levels. Finally, we combined Hp infection, Trp53 knockout, and a high-salt diet to establish a multifactor-induced gastric cancer mouse model, with preliminary phenotypic characterization.

Results:

(1) The in vitro culture and identification system for Hp was successfully established;

(2) Pretreatment with the proton pump inhibitor pantoprazole significantly inhibited gastric acid secretion, enhancing the in vivo colonization rate and clone number of Hp;

(3) Lgr5-CreERT2; Trp53^f/f mice were successfully generated to achieve conditional knockout of the Trp53 gene.;

(4) In the mouse model induced by Hp SS1 infection, high-salt diet, and Trp53 knockout, adverse phenotypes such as gastric atrophy and mucosal ulceration were observed after 5 months of intervention.

Conclusion:

A reliable in vitro culture and identification system for Helicobacter pylori (Hp) was successfully established. In vivo colonization experiments demonstrated that pretreatment with proton pump inhibitors significantly enhanced Hp colonization efficiency. Conditional knockout of the Trp53 gene was achieved by generating Lgr5-CreERT2; Trp53^f/f mice. In the mouse model combining Hp SS1 infection, high-salt diet, and Trp53 deletion, adverse gastric symptoms such as mucosal atrophy and ulceration were observed. However, long-term follow-up is still needed to clarify the role of these combined factors in the initiation and progression of gastric cancer.