Objective To explore the changes of neutrophil elastase (NE) and surfactant protein A (SP-A) in acute lung injury(ALI) rats,and the effect of antioxidant. Methods Sixty healthy mature Wister rats were divided into 2 groups, the control group and treatment group. The rats in two groups all received peritoneal injection of E. coli to establish the ALI animal model. 30 minutes after injection of E. coli,the rats in treatment group were injected reduced glutathione from vena caudalis. The levels of NE in blood and expressions of SP-A in lung tissue were detected at 3,6 and 12 hours after injection of E. coli. Results ALI symptom appeared 3 hours after injection of E. coli in the control group, obvious after 6 hours, the rats vomi-ted pink secretion after 12 hours. Lung edema and bleeding were found by pathologic examination. No obvious symptom was found in treatment group after 3 hours, slight tachypnea after 6 hours, slight edema in pulmonary tissue after 12 hours. After administration of reduced glutathione,levels of NE at 3,6 and 12 hours in the treatment group were lower than those in the control group,and indicated statistical significance in 6 and 12 hours(P <0. 05) ;Levels of SP-A in 3,6 and 12 hours in the treatment group were higher than those in the control group, and indicated statistical significance in 3,6 and 12 hours (P < 0. 05). Conclusion Dysfunction of pulmonary surfactant is secondary in ALI, degradation of SP-A is the one of reasons, the application of reduced glutathione as antioxidant, could effectively suppress NE to decompose basosexine elastin of cells and destroy surface active protein, has protective effect on ALI.

New enrofloxacin microspheres were formulated, and their physical properties, lung-targeting ability, and tissue distribution in rats were examined. The microspheres had a regular and round shape. The mean diameter was 10.06 microm, and the diameter of 89.93% of all microspheres ranged from 7.0 microm to 30.0 microm. Tissue distribution of the microspheres was evaluated along with a conventional enrofloxacin preparation after a single intravenous injection (7.5 mg of enrofloxacin/kg bw). The results showed that the elimination half-life (t(1/2beta)) of enrofloxacin from lung was prolonged from 7.94 h for the conventional enrofloxacin to 13.28 h for the microspheres. Area under the lung concentration versus time curve from 0 h to infinity (AUC(0-infinity)) was increased from 11.66 h.microg/g to 508.00 h.microg/g. The peak concentration (Cmax) in lung was increased from 5.95 microg/g to 93.36 microg/g. Three lung-targeting parameters were further assessed and showed that the microspheres had remarkable lung-targeting capabilities.
Animals ; Anti-Bacterial Agents/*adverse effects ; Drug Delivery Systems/instrumentation/*methods ; Female ; Fluoroquinolones/*adverse effects ; Half-Life ; Humans ; Injections, Intravenous ; Lung/*drug effects ; Male ; *Microspheres ; Rats ; Rats, Sprague-Dawley ; Tissue Distribution