Inhibition of Guinea Pigs Infection with Pseudomonas Aeruginosa by siRNA Targeting rhlI Gene

OBJECTIVE To investigate the inhibiton of small interfering RNA(siRNA) aimed at rhlI gene on guinea pigs infection by Pseudomonas aeruginosa biofilm. METHODS After guinea pigs model with Pseudomonas aeruginosa biofilm infection being made by trachea injection, 18 of model guinea pigs were randomly assigned to three groups, which were injected through tail vein by mixture of siRNA(50 μg·mL^-1) and liposome (siRNA group), ciprofloxacin lactate(ciprofloxacin group), or 0.9% NaCl(control group). Histopathological changes in lung and bronchial tissue were investigated. Bacteriologic test were examined in lung tissue and bronchoalveolar lavage fluid (BALF). RESULTS In siRNA group, the histology structure of lung and bronchial tissue showed no obvious abnormal. In ciprofloxacin group and control group, the structure of lung and bronchial tissue showed abnormal changes such as consolidations with inflammatory cells infiltration, bronchus mucosa degeneration with thin wall. The total bacteria number in left lung and BALF samples from siRNA group guinea pigs were significantly less than that in ciprofloxacin group(P<0.001). The biofilm formation ability of Pseudomonas aeruginosa isolated from siRNA group guinea pigs was significantly lower than that in ciprofloxacin group(P<0.001). CONCLUSION siRNA aimed at rhlI gene is able to damage biofilm in Pseudomonas aeruginosa in vivo, reduce total number of bacteria, promote diseased tissue get right, and is likely to be a new generation of drugs for bacteria biofilm infection cure.