RESUMO
Objective To investigate the dynamic changes of interleukin-1 receptor-associated kinases (IRAK-4) in hypoxic neurons and explore their role in regulation of inflammatory reaction. Methods The B35 cells exposed to hypoxia of 3% O2,5% CO2 and 92% N2 were cultured for 1,3,6, 12,24,48,72 and 96 hours respectively. Then, mRNA and protein expressions of IRAK-4 were detected by RT-PCR and Western blot, the expression of IRAK-4 in the cells were observed by laser scanning con-focal microscope (LSCM), and the concentration of IL-6 was measured by ELISA method. Results After hypoxia, the mRNA and protein expressions of IRAK-4 were increased at one hour, reached the peak at six hours (P<0.05), kept at a high level at 12 hours (P<0.05) , but decreased gradually to the normal oxygen level at 24 hours (P < 0.05) and to below the normal oxygen level at 48 hours (P < 0.05). Immunofluorescence results showed that the fluorescence intensity of IRAK-4 was gradually increased with time. The changes of IL-6 in the supernatant were positively correlated with protein expression of IRAK-4 (r =0.84, P < 0.05 ). Conclusions Hypoxia can increase the expression of IRAK-4 at transcription and translation levels in a certain period of time, which may participate in down-stream inflammatory reaction and lead to increase of IL-6 expression.
