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.
ABSTRACT
Objective To investigate the effects of photodynamic therapy (PDT) on Staphylococcus aureus and Escherichia coli strains and their laboratory-developed biofilms in vetro and the basic mechanisms of its action.Metods The bacteria were irradiated with a He-Ne laser in the presence of toluidine blue O (TBO).The colony forming units (CFU) of each strain were countde before and after treatment,and the uptakd of TBO by the bacteria was determined using fluorospectrophotometry. Results With a constant light dose,the bactericidal effects of PDT against the two bacteria cultures increasde woth the concentration of TBO,with the strongest bactericidal effect after PDT treatment more than 90%.S.aureus seemed to be more sensitive to PDT than E.coli,though the amount of TBO absorbed by the E.coli cells was significantly larger.The effects of PDT on mature and immature biofilms formed by the two strains showed no significant difference.The bactericidal rate was 20% to 30%.Conclusion Ge-Ne laser irradiation associated with TBO demonstrated significcant photodynamic bactericidal effects on S.arueus and E.coli strains cultivatde in vitro,but the iffects on their biofilms wer limitde.The efficacy of PDT was independent of the absorption of TBO into the bacterial cells.
ABSTRACT
Objective To study the effects of He-Ne laser irradiation dosage on the expression of heat shock protein ( HSP70) and CyclinD_1 in rats with chronic atrophic gastritis ( CAG). Method Fifty-two adult male Wistar rats were randomly divided into five groups: a normal control group, model group and three groups receiving different doses of He-Ne laser irradiation. CAC was induced using an enema of 2% sodium salicylate and 30% alcohol combined with irregular fasting and forced exercise as pathogenic factors. Laser irradiation was applied for 20 days (large dose 6.24 J/cm~2 , medium dose 4. 80 J/cm~2, small dose 3. 36 J/cm~2). The changes in HSP70 and CyclinD_1 expression were observed. Results The expression of HSP70 and CylinD_1 were highest in the normal control group and the small dose laser group. Compared with the model group, the average expression of HSP70 and CyclinD_1 increased significantly in the small dose group. Conclusions Irradiation with a He-Ne laser at 3. 36 J/cm~2 provides good adjuvant therapeutic effect for CAG in rats. After irradiation, the expression of HSP 70 and CyclinD_1 increased. HSP is important in improving mucosal defenses and promoting cell proliferation in CAG, and it can be promoted through small doses of He-Ne laser irradiation.