High-dose proinflammatory cytokines induce apoptosis of hair bulb keratinocytes in vivo
✍ Scribed by R. Rückert; G. Lindner; S. Bulfone-Paus; R. Paus
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 489 KB
- Volume
- 143
- Category
- Article
- ISSN
- 0007-0963
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✦ Synopsis
Background:
Hair loss following skin inflammation may in part be mediated by keratinocyte (kc) apoptosis. while the effects of different cytokines or other apoptosis stimulating agents such as interferon (ifn)-gamma or tumour necrosis factor (tnf)-alpha on kc apoptosis in vitro have been addressed in several studies, little is known about the effects of proinflammatory cytokines on kc apoptosis in vivo.
Objectives:
To study the effects of intradermally injected tnf-alpha, interleukin (il)-1beta and ifn-gamma on kc apoptosis in the back skin of c57bl/6 mice.
Methods:
Apoptosis in epidermal and hair bulb kcs was analysed by immunohistology using tunel staining.
Results:
Injection of tnf-alpha induced a significantly higher number of apoptotic cells within the epidermis than vehicle; all three proinflammatory cytokines together further increased their number. intrafollicular hair bulb kcs were much more susceptible to apoptosis induction by tnf-alpha or il-1beta; their injection significantly upregulated apoptosis after 6 h, which was further increased after 24 h. the combination of all cytokines together accelerated intrafollicular apoptosis after 6 h by doubling the number of apoptotic cells per hair bulb, compared with the effects of tnf-alpha or il-1beta alone.
Conclusions:
These data suggest that programmed cell death of proliferating kcs in vivo can be induced by proinflammatory cytokines.