氦氖激光照射对萎缩性胃炎大鼠增殖细胞核抗原及B细胞淋巴瘤／白血病-2表达的影响

Effects of He-Ne laser irradiation on the expression of proliferating cell nuclear antigen and B cell lymphoma/leukemia-2 protein in the gastric mucosa of rats with chronic atrophic gastritis

目的观察氦氖激光照射对慢性萎缩性胃炎（CAG）大鼠增殖细胞核抗原（PCNA）、B细胞淋巴瘤／白血病-2（Bcl-2）蛋白表达的影响，从而探讨氦氖激光照射与胃黏膜癌前病变、细胞凋亡间的关系。方法将实验大鼠随机分为正常组、模型组及激光组，模型组及激光组大鼠给予水杨酸钠和酒精混合溶液灌胃，并辅以劳累、饥饱失常等刺激因素以制作CAG模型。激光组大鼠于制模成功后给予氦氖激光照射，照射剂量为3．36J／cm2，每次7min，每天1次，连续照射20d为1个疗程。于激光照射20d后通过光镜观察各组大鼠胃黏膜炎症程度及壁细胞形态、结构等，采用免疫组化法检测各组大鼠胃窦黏膜Bcl-2、PCNA表达。结果光镜观察发现模型组大鼠胃黏膜层腺体萎缩、炎性细胞浸润，激光组炎性细胞减少，细胞形态、结构均恢复或接近正常组水平。免疫组化结果显示在胃黏膜萎缩过程中，模型组PCNA及Bcl-2表达均较正常组升高（P〈0．05），激光组大鼠经氦氖激光照射后，其PCNA及Bcl-2表达均明显降低，与模型组间差异具有统计学意义（P〈0．05）。结论CAG模型大鼠胃黏膜细胞处于高增殖状态，氦氖激光照射能降低CAG大鼠胃黏膜内PCNA及Bcl-2表达，强化细胞增殖调控功能，诱导细胞凋亡，阻止其向癌变方向发展。

Objective To study the effects of He-Ne laser irradiation on histological changes and the expression of proliferating cell nuclear antigen （PCNA） and B-cell lymphoma/leukemia-2 （Bcl-2） in the gastric mucosa of rats with chronic atrophic gastritis （CAG） so as to elucidate the relationship of He-Ne laser irradiation with precancerous lesions and apoptosis in the gastric mueosa. Methods The rats were divided into a normal group, a model group and a laser group. A model of CAG was established by gastric perfusion with a mixture of sodium salicylate and alcohol combined with irregular fasting and forced exercise. A He-Ne laser was used to irradiate the rats at 3.36 J/cm2 for 7 min daily for 20 d. Histopathological changes including the severity of inflammation in the gastric mueosa and the morphology and structure of the parietal cells were observed with a light microscope, and the expression of PCNA and Bcl-2 was detected with immunohistochemieal methods. Results The pathologic morphological changes in the gastric mucosa of the model group were atrophy of the glands of the gastric mueosa and notable inflammatory infiltration. But in the laser group inflamed cells decreased, and the morphology, structure and volume of the cells all recovered close to normal. The immunohistochemistry results showed that during the atrophy of the gastric mucosa the expression of PCNA and Bcl-2 was elevated, and it was significantly higher in the model group than in the normal group. After irradiation the expression of PCNA and Bcl-2 was significantly lower. Conclusions There was hyper-proliferation in the gastric mucosa of the CAG model rats, with high expression of apoptosis suppressor PCNA and Bcl-2 proteins. Laser irradiation can reduce the expression of PCNA and Bcl-2, enhance cell proliferation and induce apoptosis, preventing the development of cancer. Laser irradiation has a good adjuvant therapeutic effect for all the pathological changes observed.