Figure 6

The effects of quercetin on MMP-9 activity and pro-inflammatory cytokine production in LPS-induced ALI. BALF were collected 24 hours after an intratracheal LPS challenge and cultured with quercetin or vehicle for 1 hour. After the medium was changed, BALF cells were cultured with vehicle or quercetin for another 18 hours and the supernatant was collected. (A) MMP-9 activity in the supernatant was determined by zymography. Latent (92 kDa) and active (88 kDa) MMP-9 and latent (72 kDa) MMP-2 activities are observed as clear zones of lysis against a dark background. MMP-9 activities were quantified by measuring the band intensities. (B) The production of TNF-α, IL-1β, and IL-6 in the supernatant was determined by ELISA. Results are shown as the mean ± SD (*p < 0.05) of three independent experiments.