Objective:To investigate the effects of theaflavin-loaded poly lactic-co-glycolic acid(PLGA) nanoparticles by high frequency aerosol inhalation on MUC5 AC of inflammatory airway. Methods:Theaflavin-loaded PLGA nanoparticles were prepared by improved methods. The diameter of nanoparticles was detected;entrapment rate and drug-loading were determined;in vitro release test was conducted. SD rats were divided into control group(group A

n=8)

cigarette inhaling group(group B

n=8)

and intervention group(group C

n = 8). All the rats were sacrificed on the 30 th day and samples were obtained. MUC5 AC m RNA in each group was examined by RT-PCR. Changes in protein expression of MUC5 AC were observed by ELISA. Changes of MUC in airway were compared by histochemistry. The data were analyzed with SPSS 12. 0 software. Results:Theaflavin-loaded PLGA nanoparticles prepared by improved methods were stable in property

uniform in size with an average of(108.24 ±2.86) nm

and suitable for nebulized inhalation. Both MUC5 AC m RNA and protein expression in cigarette inhaling group increased obviously and there were significant differences compared with those of control group(P = 0. 000). But after the administration of theaflavin-loaded PLGA nanoparticles

all the indexes decreased obviously compared with those in cigarette inhaled group(P = 0. 001)

and RT- PCR for MUC5 AC m RNA expression showed similar electrophoresis results. Besides

histochemistry also indicated that after high frequency nebulized inhalation of theaflavin-loaded PLGA nanoparticles

MUC expression of the airway decreased significantly. Conclusion:Theaflavin-loaded PLGA nanoparticles prepared by improved methods are stable in property

uniform in size

which by high frequency nebulized inhalation

can inhibit the high secretion of MUC5 AC in inflammatory airway. It provides a new way to the exploitation and application of theaflavin.