老龄与非老龄大鼠胃黏膜组织结构的增龄变化

目的 比较Wistar大鼠胃黏膜组织结构的随龄变化. 方法 选择3月龄(体质量200～300 g)及22月龄(体质量600～800 g)清洁级健康Wistar大鼠各6只.光镜下观察老龄、非老龄大鼠胃黏膜腺体厚度、黏膜肌层厚度、固有腺体数量;胃蛋白酶试剂盒生化检测胃黏膜组织胃蛋白酶活力,免疫组化方法检测大鼠黏膜增殖细胞核抗原(PCNA)的表达. 结果 老龄和非老龄大鼠胃黏膜均未见肠上皮化生、不典型增生及肿瘤的发生.老龄组胃黏膜腺体厚度低于非老龄组,分别为(271.5±47.4)μm和(350.9±53.3)μm(t=2.731,P<0.05),老龄组胃黏膜肌层较非老龄组增厚,分别为(98.1±13.1)±μm和(62.4±10.6)μm(t=5.174,P<0.001).胃黏膜组织蛋白酶含量老龄组为(3.011±1.222)U,非老龄组为(4.733±1.304)U,老龄组明显下降(t=2.361,P=0.05).非老龄组大鼠胃黏膜中PCNA阳性细胞主要位于胃腺颈部增殖细胞带,表达规律,细胞核染色阳性;老龄组胃腺颈部增殖细胞带PCNA阳性表达较非老龄组厚度降低,位置下移,偏向于黏膜肌层. 结论 老龄大鼠胃腺体萎缩、黏膜肌层增厚的发生率增加,胃蛋白酶原分泌减少,胃颈腺干细胞的增殖能力下降.

Changes of tissue structure of gastric mucosa with aging in rats

Objective To observe the changes of tissue structure of gastric mucosa with aging in rats. Methods Twelve healthy Wistar rats were divided into two groups: aged (12 months,n=6) and non-aged rats (3 months,n=6). The thickness of gastric gland and muscular layer of mucosa were observed under the light microscopy. Pepsin activity and the expression of proliferating cell nuclear antigen (PCNA) were detected by biochemical method and immunohistochemical method respectively. Results Intestinal metaplasia, dysplasia and adenoma were not found in gastric mucosa in two groups. In aged versus non-aged rat group, the thickness of gastric gland was decreased (271.5±47.4) μm vs. (350.9±53.3) μm, t=2.731, P<0.05], while the thickness of muscular layer of mucosa was increased (98.1±13.1) μm vs. (62.4±10.6)μm, t=5.174, P<0.01]. The content of pepsin in aged rats were lower than in non-aged rats(3. 011±1. 222) U vs. (4.733±1.304) U, t= 2.361, P<0.05]. Immunohistochemistry results showed that the positive cells of PCNA were located in gastric stem cells in cervical part, and the thickness of the gastric stem cells was decreased in aged rats. Conclusions The incidences of gastric gland atrophy and muscular layer hypertrophy are increased, and the secretion of pepsinogen and the proliferation ability of gastric stem cells are decreased in aged rats.