Luteolin decreases HaCaT keratinocyte proliferation without affecting ATP production.

<p>HaCaT cells were incubated with luteolin (10–100 µM) for up to 3 days. (A) Cell proliferation was examined using a XTT-based assay. (B) Intracellular ATP content was determined using an ATP assay kit (n = 3, ns = not significant, * p<0.05).</p

Luteolin reduces TNF-stimulated mRNA expression of NFKB1 (NF-κB p50) and RELA (NF-κB p65) in keratinocytes.

<p>The effect of luteolin on mRNA expression levels of two genes encoding NF-κB subunits were investigated using qRT-PCR. HaCaT cells were pretreated with luteolin (10–100 µM, 30 min) before stimulation with TNF (50 ng/mL, 6 h): (A) NFKB1, (B) RELA. NHEKs were pretreated with luteolin (10 µM, 30 min) before stimulation with TNF (50 ng/mL, 6 h): (C) NFKB1, (D) RELA. (n = 3, * p<0.05).</p

Luteolin inhibits IL-6, IL-8 and VEGF production from TNF-triggered HaCaT keratinocytes.

<p>HaCaT cells were pretreated with luteolin (1–100 µM) for various times as indicated and then stimulated with TNF (50 ng/mL, 24 h). Mediators in the supernatant fluids were measured by ELISA: (A) IL-6; (B) IL-8; (C) VEGF. The mRNA expression levels of (D) IL-6, (E) IL-8 and (F) VEGF were also determined after TNF stimulation (50 ng/mL, 6 h) by qRT-PCR (h = hours; n = 3, * p<0.05).</p

Luteolin reduces TNF-triggered NF-κB activation in HaCaT keratinocytes.

<p>HaCaT cells were incubated with luteolin (10–100 µM, 6 h) and then stimulated with TNF (50 ng/mL, 15 min). (A) TNF-triggered phosphorylation of NF-κB p65 was detected using a Multi-Target Sandwich ELISA kit and is presented as fold changes relative to control. (B) NF-κB p65 DNA-binding activity in the nuclear extract was examined and expressed as fold changes relative to control. (C) Nuclear translocation of NF-κB p65 was determined using Western blot and quantified by densitometry (D). The Western blot shown in (C) was representative of 3 independent experiments. (n = 3, * p<0.05).</p

Luteolin decreases production of IL-6, IL-8 and VEGF in TNF-triggered primary NHEKs.

<p>NHEKs were pretreated with luteolin (10 µM, 30 min) before stimulation with TNF (50 ng/mL). Mediator release was measured at 24 h by ELISA: (A) IL-6; (B) IL-8; (C) VEGF. The mRNA expression levels were measured at 6 h by qRT-PCR: (D) IL-6; (E) IL-8; (F) VEGF (n = 3, * p<0.05).</p