OBJECTIVETo study if the expression of maspin protein in respiratory epithelial cells was downregulated through IκB kinase-α (IKKα)-controlled mechanism in an Aspergillus fumigatus-induced model in rat.

METHODSInactivated Aspergillus fumigatus hyphae (AFH) suspension was used to induce respiratory epithelial cells (REC) cultured in vitro in rat, with PBS buffer as control. By RT-PCR, the mRNA expression of maspin was quantified, and by immunocytochemistry, the expression of maspin and IKKα in REC was observed. Furthermore AFH (from level 1 to level 3) suspension was prepared to induce REC. Then Western blot hybridization technique was used to detect the expression of maspin and IKKα protein. All data were processed by analysis of variance and two-variable correlation analysis.

RESULTSBy RT-PCR, a statistically significant (t = 2.463, P < 0.05) expression of maspin mRNA was found (0.128 ± 0.059 in AFH group, 2.972 ± 0.353 in control group). By Immunocytochemistry, the difference of maspin protein color in different groups was shown statistically significant in integrated scoring (t = 3.721, P < 0.05, weak positive in AFH group, moderately positive in control group). While in IKKα color study, the difference between the two groups was also statistically significant (t = 6.825, P < 0.05) in integrated scoring, with a moderate positive in AFH group and weak positive in control group. By Western Blot hybridization, grayscale ratio of maspin and β-actin was 0.912 ± 0.023 in control group, 0.607 ± 0.030, 0.476 ± 0.019, 0.416 ± 0.017 in AFH 1-3 groups, respectively, with a statistically significant difference within the four groups (F = 281.91, P < 0.05); While grayscale ratio of IKKα and β-actin was 0.624 ± 0.012 in control group, 0.739 ± 0.020, 0.778 ± 0.010, 0.927 ± 0.017, respectively, in AFH 1-3 groups; with a statistically significant difference within the four groups(F = 200.91, P < 0.05). Moreover, the difference between any two groups from both AFH group (including subgroup 1, 2 and 3) and control group was statistically significant. Two-variable correlation analysis indicated a negative correlation between expression of maspin and IKKα (r = -0.911, P < 0.05).

CONCLUSIONSInduced by Aspergillus fumigatus, the rat respiratory epithelia might upregulate the expression of IKKα with a downregulated expression of maspin protein.