Figure 6.

IL1B gene expression is not significantly up‐regulated in aged skin following tumour necrosis factor‐α (TNF‐α) treatment. Quantitative PCR was used to assess mRNA expression of genes involved in interleukin‐1 (IL‐1) and TNF‐α signalling in young and aged human skin (n = 6/ age group) following 24‐hr culture with control medium, 25 ng/ml IL‐1β and 250 ng/ml TNF‐α. Results are presented as the fold change in gene expression for each individual relative to the average gene expression in the young unstimulated (T0) group. Each circle represents a different individual and the horizontal line indicates the mean, ****P < 0·0001, ***P < 0·001, **P < 0·01, *P < 0·05.