Erythromycin enhances the anti-inflammatory activity of budesonide in COPD rat model

Glucocorticoids (GCs) have been widely applied to treat patients with chronic obstructive pulmonary disease (COPD). But the effect of GCs was not ideal. This study was to observe whether erythromycin could enhance the anti-inflammatory activity of budesonide in COPD model rats and to explore the mechanism involved. In this study, male Sprague-Dawley rats were divided into five groups: healthy control group (H group), COPD model group (C group), erythromycin group (E group), budesonide group (B group) and erythromycin + budesonide group (E+B group). The rats in groups of C, E, B and E+B were developed into COPD models. Different groups were given different drug interventions. The levels of 8-iso-PGF2α, IL-8, and TNF-α in BALF and serum were measured with ELISA. The protein expression levels of HDAC2, PI3K, and p-AKT in lung tissue were measured with Western-blot and immunohistochemistry. The levels of 8-iso-PGF2α, IL-8, and TNF-α in BALF and serum were lower in E+B group than those in B group and C group (all P<0.001).The protein expression level of HDAC2 was higher and PI3K and p-AKT were lower in E+B group than those in B group and C group (all P<0.001). Moreover, the expression levels of HDAC2 were negatively correlated with the levels of 8-iso-PGF2α, IL-8 and TNF-α both in serum and BALF and the expression levels of PI3K and p-AKT among the five groups, with all P<0.001. We conclude that erythromycin can enhance the anti-inflammatory activity of budesonide in COPD model rats, possibly through inhibiting the PI3K/AKT pathway and enhancing the activity of HDAC2.