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Reduced superoxide dismutase activity in UVB-induced hyperproliferative pig epidermis
Y Hashimoto1, N Ohkuma, H Iizuka
1Department of Dermatology, Asahikawa Medical College, Japan.
Archives of Dermatological Research
|January 1, 1991
Summary
UVB irradiation initially slows, then boosts keratinocyte proliferation. This increase correlates with reduced superoxide dismutase (SOD) activity, primarily from decreased copper-zinc SOD (Cu,Zn-SOD).
Area of Science:
- Dermatology
- Biochemistry
- Cell Biology
Background:
- Superoxide dismutase (SOD) activity is often reduced in hyperproliferative skin cells.
- Understanding the link between SOD and keratinocyte proliferation is crucial for skin health research.
Purpose of the Study:
- To investigate the relationship between epidermal SOD activity and keratinocyte proliferation following UVB irradiation.
- To determine the specific SOD isoenzyme responsible for changes in activity.
Main Methods:
- In vivo UVB irradiation was applied to pig epidermis at twice the minimum erythema dose.
- Keratinocyte proliferation was assessed by thymidine incorporation and mitotic counts.
- Superoxide dismutase (SOD) activity, including Cu,Zn-SOD and Mn-SOD, was measured.
Main Results:
- UVB irradiation initially suppressed thymidine incorporation and mitosis for 48 hours.
- Keratinocyte proliferation significantly increased at 96 hours post-irradiation.
- SOD activity remained stable initially, then decreased by 50% at 96 hours, mainly due to reduced Cu,Zn-SOD activity.
Conclusions:
- UVB-induced keratinocyte hyperproliferation is associated with decreased SOD activity.
- The reduction in SOD activity is primarily attributed to diminished Cu,Zn-SOD levels.
- No changes in SOD activity were observed during the initial hypoproliferative phase.