Objective To explore the effect of simvastatin on airway mucus hypersecretion in rats.   Methods Rat airway mucus hypersecretion was induced by acrolein. Forty-two male SD rats were randomly divided into 7 groups

with 6 rats in each group. The rats in groups D

E

F were intragastrically administered simvastatin (5

10

20 mg/kg respectively) 1 d before spray atomization of acrolein once a day for 12 d and those in group G were simultaneously given 20 mg/kg simvastatin and 20 mg/kg mevalonate intraperitoneally. The rats in groups A and B received no spray atomization of acrolein

and those in group B were given 20 mg/kg simvastatin intragastically once a day

which both served as control. Mucin and mucin5ac were detected with Alcian blue-periodic acid sthiff and immunohistochemistry

and mucin5ac mRNA by RT-PCR.     Results Acrolein significantly induced the expression of mucin5ac mRNA and protein in bronchial epithelium

and increased the concentration of mucin and macrophage number in BALF. Simvastatin significantly suppressed bronchial mucin5ac expression and reduced the number of macrophages and the concentration of mucin. The effect of simvastatin can be partly reversed by mevalonate.   Conclusion Simvastatin inhibits airway mucus hypersecretion induced by acrolein

which might be related to the reduction of macrophage infiltration through mevalonic acid pathway.