- Email: [email protected]
Distinct cutaneous cytokine secretion profiles induced in mice by skin irritant and sensitising chemicals
44
Abstracts / Toxicology 226 (2006) 12–77
Distinct cutaneous cytokine secretion profiles induced in mice by skin irritant and sensitising chemicals Marie Cumberbatch, Rebecca J. Dearman, Ian Kimber Syngenta CTL, Alderley Park, Macclesfield, Cheshire SK10 4TJ, UK E-mail address: [email protected] (M. Cumberbatch) Epidermal langerhans cells (LC) recognise and respond to a wide variety of cutaneous insults, including exposure to sensitising and irritant chemicals. In response to such stimuli LC undergo a phenotypic and functional maturation that is required for their migration from the skin and for the development of immune responses. We have speculated that cutaneous cytokines released in response to such stimuli will impact not only on LC function but also on the quality of the immune response induced. We have examined, therefore, the early kinetics of cutaneous cytokine secretion stimulated in BALB/c strain mice (n = 5–10/group) following topical application to the dorsal surface of both ears of the contact allergens 2,4-dinitrochlorobenzene (DNCB; 1%) or oxazolone (Ox; 0.5%), the respiratory allergen trimellitic anhydride (TMA; 25%), or the skin irritant sodium lauryl sulphate (SLS; 10%). Control mice were exposed to the relevant vehicles: acetone:olive oil (4:1; AOO) for DNCB, Ox and TMA, or dimethylformamide (DMF) for SLS. Dorsal ear skin explant cultures were established 1, 2 and 4 h following exposure of mice to chemical, or appropriate vehicle, and supernatants harvested 17 h later for measurement of cytokine content by protein array for interleukin (IL)-1␣, IL-1, IL-2, IL-10, IL-12p70 and tumour necrosis factor-␣ (TNF-␣). It was found that both DNCB and Ox were associated with significant (p < 0.005, Student’s two-sided t-test) IL-2 secretion at all time points examined. Thus, IL-2 levels in culture supernatants increased from less than 2 pg/ml in all AOO-control samples (1, 2 and 4 h) to 29.2 ± 5.2, 146.1 ± 36.9 and 31.6 ± 7.8 pg/ml for DNCB and 51.6 ± 7.1, 75.4 ± 11.1 and 35.0 ± 7.8 pg/ml for Ox, 1, 2 and 4 h following exposure, respectively. No such changes in IL-2 secretion were observed for TMA or SLS. Both DNCB and Ox caused significant increases in IL-1 production 2 h (DNCB: 1.5-fold, p < 0.05; Ox: 2.5-fold, p < 0.05) and 4 h (DNCB: 6.0-fold, p < 0.005; Ox: 3.6-fold, p < 0.05) following treatment, with no significant changes in production of this cytokine being observed for TMA or SLS. In addition, elevated TNF␣ levels were recorded for both DNCB (2 h: 2.2-fold,
p < 0.05) and Ox (1 h: 2.5-fold, p < 0.005; 2 h: 2.9-fold, p < 0.005). Although TMA failed to enhance TNF-␣ secretion, exposure of mice to SLS did result in production of this cytokine (1 h: 1.8-fold, p > 0.05; 2 h: 1.6-fold, not significant). All chemicals (DNCB, Ox, TMA and SLS) were associated with some increase in IL-1␣ release over the exposure period. Interestingly, TMA induced significant IL-10 secretion at all time points as described previously (Cumberbatch et al., 2005), whereas DNCB and Ox stimulated variable but significant increases in this cytokine 2–4 h following exposure. Production of IL-12p70 remained unchanged throughout for all chemical treatments. Taken together these results suggest that chemical contact allergens induce a characteristic early cutaneous cytokine secretion profile that is distinct from the range of cytokines stimulated by a chemical respiratory allergen or a skin irritant. Varying patterns of cytokine production in the skin in response to different environmental stimuli may impact upon LC function and thereby contribute to the development of divergent cutaneous immune and inflammatory responses tailored to suit the nature of the insult. Reference Cumberbatch, M., Clelland, K., Dearman, R.J., Kimber, I., 2005. J. Immunol. 175, 43–50.
doi:10.1016/j.tox.2006.05.064 Molecular mechanisms associated with aberrant liver growth and carcinogenesis in F344 rats treated with phenobarbital Richard A. Currie, Jacky Dow, Claire Sadler, Fei Ling Lim, Adam Hargreaves, Tom Aldridge, Jayne Wright, Catherine J. Waterfield, John Ashby, Ian Kimber, George Orphanides, Jonathan G. Moggs Syngenta CTL, Alderley Park, Macclesfield SK10 4TJ, UK E-mail address: [email protected] (R.A. Currie) Rodent nongenotoxic carcinogens (NGC) alter cell growth, proliferation and apoptosis. The assessment of the potential hazard to humans will be aided by identification of the molecular pathways involved. To identify novel markers of aberrant proliferation, we investigated the molecular mechanisms of liver growth, proliferation and hypertrophy induced in rats by NGC; in the first instance using phenobarbitone (PB) which is known to
Abstracts / Toxicology 226 (2006) 12–77
Distinct cutaneous cytokine secretion profiles induced in mice by skin irritant and sensitising chemicals Marie Cumberbatch, Rebecca J. Dearman, Ian Kimber Syngenta CTL, Alderley Park, Macclesfield, Cheshire SK10 4TJ, UK E-mail address: [email protected] (M. Cumberbatch) Epidermal langerhans cells (LC) recognise and respond to a wide variety of cutaneous insults, including exposure to sensitising and irritant chemicals. In response to such stimuli LC undergo a phenotypic and functional maturation that is required for their migration from the skin and for the development of immune responses. We have speculated that cutaneous cytokines released in response to such stimuli will impact not only on LC function but also on the quality of the immune response induced. We have examined, therefore, the early kinetics of cutaneous cytokine secretion stimulated in BALB/c strain mice (n = 5–10/group) following topical application to the dorsal surface of both ears of the contact allergens 2,4-dinitrochlorobenzene (DNCB; 1%) or oxazolone (Ox; 0.5%), the respiratory allergen trimellitic anhydride (TMA; 25%), or the skin irritant sodium lauryl sulphate (SLS; 10%). Control mice were exposed to the relevant vehicles: acetone:olive oil (4:1; AOO) for DNCB, Ox and TMA, or dimethylformamide (DMF) for SLS. Dorsal ear skin explant cultures were established 1, 2 and 4 h following exposure of mice to chemical, or appropriate vehicle, and supernatants harvested 17 h later for measurement of cytokine content by protein array for interleukin (IL)-1␣, IL-1, IL-2, IL-10, IL-12p70 and tumour necrosis factor-␣ (TNF-␣). It was found that both DNCB and Ox were associated with significant (p < 0.005, Student’s two-sided t-test) IL-2 secretion at all time points examined. Thus, IL-2 levels in culture supernatants increased from less than 2 pg/ml in all AOO-control samples (1, 2 and 4 h) to 29.2 ± 5.2, 146.1 ± 36.9 and 31.6 ± 7.8 pg/ml for DNCB and 51.6 ± 7.1, 75.4 ± 11.1 and 35.0 ± 7.8 pg/ml for Ox, 1, 2 and 4 h following exposure, respectively. No such changes in IL-2 secretion were observed for TMA or SLS. Both DNCB and Ox caused significant increases in IL-1 production 2 h (DNCB: 1.5-fold, p < 0.05; Ox: 2.5-fold, p < 0.05) and 4 h (DNCB: 6.0-fold, p < 0.005; Ox: 3.6-fold, p < 0.05) following treatment, with no significant changes in production of this cytokine being observed for TMA or SLS. In addition, elevated TNF␣ levels were recorded for both DNCB (2 h: 2.2-fold,
p < 0.05) and Ox (1 h: 2.5-fold, p < 0.005; 2 h: 2.9-fold, p < 0.005). Although TMA failed to enhance TNF-␣ secretion, exposure of mice to SLS did result in production of this cytokine (1 h: 1.8-fold, p > 0.05; 2 h: 1.6-fold, not significant). All chemicals (DNCB, Ox, TMA and SLS) were associated with some increase in IL-1␣ release over the exposure period. Interestingly, TMA induced significant IL-10 secretion at all time points as described previously (Cumberbatch et al., 2005), whereas DNCB and Ox stimulated variable but significant increases in this cytokine 2–4 h following exposure. Production of IL-12p70 remained unchanged throughout for all chemical treatments. Taken together these results suggest that chemical contact allergens induce a characteristic early cutaneous cytokine secretion profile that is distinct from the range of cytokines stimulated by a chemical respiratory allergen or a skin irritant. Varying patterns of cytokine production in the skin in response to different environmental stimuli may impact upon LC function and thereby contribute to the development of divergent cutaneous immune and inflammatory responses tailored to suit the nature of the insult. Reference Cumberbatch, M., Clelland, K., Dearman, R.J., Kimber, I., 2005. J. Immunol. 175, 43–50.
doi:10.1016/j.tox.2006.05.064 Molecular mechanisms associated with aberrant liver growth and carcinogenesis in F344 rats treated with phenobarbital Richard A. Currie, Jacky Dow, Claire Sadler, Fei Ling Lim, Adam Hargreaves, Tom Aldridge, Jayne Wright, Catherine J. Waterfield, John Ashby, Ian Kimber, George Orphanides, Jonathan G. Moggs Syngenta CTL, Alderley Park, Macclesfield SK10 4TJ, UK E-mail address: [email protected] (R.A. Currie) Rodent nongenotoxic carcinogens (NGC) alter cell growth, proliferation and apoptosis. The assessment of the potential hazard to humans will be aided by identification of the molecular pathways involved. To identify novel markers of aberrant proliferation, we investigated the molecular mechanisms of liver growth, proliferation and hypertrophy induced in rats by NGC; in the first instance using phenobarbitone (PB) which is known to