Effects of selective phosphodiesterase 4 inhibitor on expression of aquaporin 5 in airway mucus hypersecretion model of rats

Abstract

To explore the mechanism of selective phosphodiesterase 4 (PDE4) inhibitor and observe its effects on the in vitro expression of aquaporin 5 (AQP5) in a rat model of airway mucus hypersecretion. Forty healthy male rats were randomized into 4 groups (n = 10 each). The normal control and drug control groups underwent normal saline aerosol inhalation or YM976 lavage respectively for 12 days while the model and treatment groups acrolein atomization inhalation or acrolein atomization inhalation plus YM976 lavage respectively for 12 days. The middle lobe of right lung were fixed, embedded and stained by hematoxylin and eosin to observe the histological changes of small airway. The mucin secretion by goblet cells in lung tissue was tested by alcian blue staining. And the effects of selective PDE4 inhibitor on the expression of AQP5 were detected by immunohistochemical stain. Reverse transcription-polymerase chain reaction and Western blot were used to determine the levels of AQP5 mRNA and protein. In the treatment group, mucus gland hyperplasia and airway mucus hypersecretion and positive staining area ratio of alcian blue staining decreased significantly compared with the model group (10.23% ± 0.94% vs 14.74% ± 1.06%, P < 0.05). And the expression of AQP5 mRNA (1.26 ± 0.19) and protein (0.56 ± 0.13) also declined significantly versus the model group ((0.96 ± 0.17), (0.43 ± 0.15), P < 0.05). Selective PDE4 inhibitors alleviate the pathological damage of lung tissue and enhance the expression of AQP-5 in airway mucus hypersecretion.