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

Abstract

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 mucosa. 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 mucosa 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 immunohistochemical methods. Results The pathologic morphological changes in the gastric mucosa of the model group were atrophy of the glands of the gastric mucosa 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. Key words: Chronic atrophic gastritis; He-Ne lasers; Proliferating cell nuclear antigen; B-cell lymphoma/leukemia-2 ; Precancerous lesions